Your pets are scratching

It’s hard to tell when fleas are infesting your home. You’d likely only notice a few anyway because they’re so small. What also complicates things is that only 5% of household fleas will live on your pet, as the eggs don’t adhere to hair like human lice. Instead, they get into tiny spaces and are incredibly hardy. Vacuum thoroughly and keep an eye out for scratching.
You see a lot of spiders

The common house spider is a sensitive little creature. They enjoy living al-fresco but the smallest shift in temperature or weather makes them want to migrate indoors. This isn’t an infestation, they try to stay out of the way and eat your bugs. If you see a lot of them out in the open hunting, though, their food source likely is a new, worse infestation.
You see lots of spider legs

Sticking with wall-crawlers, spiders grow by breaking out of their outer layers of hard skin, the new surface then hardens forming a new carapace. They can even regrow limbs during this process and do so a few times a year, so a pile of these in one area means one spider that has been there a while, while many scattered piles imply an invasion.
You see ladybugs

As absolutely captivating as they look, ladybugs are savage predators in the insect world. They’re an important companion for gardeners, as plant-eating aphids are their favourite meal, but seeing them inside means they’ve found something else for dinner. Mites, scale insects and whiteflies are all domestic bugs they’re doing you a favour by Darwin-ing, so leave them be and focus on the real culprit.
You hear tapping in your walls

On the off chance it isn’t a demon from the spirit world, tapping in your walls could be termites chewing their way through your framing lumber. They make a slight knock while eating as their heads bang against the wood but, when agitated, the sound of a group frantically trying to flee is very audible and piercing.
You spot dampness on the walls

Moisture on walls is always an indicator that something is wrong and the longer you leave it, the worse it gets. A dripping pipe will expand any wood that gets wet, which termites love and will eat away at the weakening foundation. The damp and now termite faeces-saturated wood is the perfect breeding ground for mould and fungi, and they can seriously harm your health.
You see piles of “fish scales”

These small, scale-like insect parts are usually found in piles around windowsills and in corners. They’re the discarded wings of termites that have found a mate and somewhere to call home. Termite queens can life for up to 20 years in ideal conditions, so ideally you want to usurp before her as she settles down for her married life.
Your house gets a mud-trimming

Maybe aesthetically it adds a bit of character, but it’s doing nothing for the re-sale value. These trenches are built by termite soldiers out of dirt and saliva to protect them from the elements. That isn’t an “elbow grease” type metaphor; they literally use their spit to aid their constructions, which also partially digests it and makes it a decent source of food.
You spot some “wooden pellets”

Another sign of the termite scourge is these small, wood-looking pellets. They’re the waste left behind as the insects tunnel their way through whatever is in front of them, so spotting them outside your home means they’re nearby – but probably not set to work on your foundations.
Your paint is peeling

Peeling paint is almost always a sign of moisture. That can be confusing because often the paint peelings and whatever material is underneath can seem bone dry. In that case, it could be a humidity issue, but bubbling, tearing and discolouration are all sure signs of moisture, which could be coming from infestation.
You see ‘sesame seeds’

Mice, rats, and many other rodents are known to leave small, dark brown to black droppings. They do appear, at a distance, to be sesame seeds, which presumably you know the chances of being spilt in your kitchen, so they’re not hard to distinguish after a glance. These droppings are usually around crumbs of food, like behind toasters or in cupboards.
Shredded paper and fibre in corners

This is a concerning sign, especially if you don’t own a shredder. Pet mice are often given shredded paper for their bedding, but you can also give them soft paper and they’ll tear it themselves. It’s a fascinating behaviour to watch, but it does mean that rats or mice are living quite comfortably nearby.
You hear faint flutters

Bats are creatures that love darkness and peace. Their echolocation is one of the loudest sounds in the animal kingdom, but its frequency is too high-pitched for us to hear. Their stealthy nature means you’ll only hear them in your walls if they’re startled and start flapping, such as when slamming a door.
Somebody has been drilling holes in your walls

Rarely is any reported ‘spike in crime’ what it seems, so, before you start googling what explosives fit in drill holes, allow the carpenter bee to make your acquaintance. They only burrow for materials to nest with, but can return year after year to continue their hard work. You’ll spot piles of sawdust next to their handiwork.
You have an anthill near your home

Spotting the odd ant around your house is no big deal, especially if they’re on their own. If they’re part of a rank and file situation, they’re emerging from wall cracks, or you have a hill around your home, this could be a sign there are more than you realise. Certain species are worse than others, but you will want them taken care of ASAP.
You leave your windows open

Insects evolve at a rate thousands of times faster than humans, they already know all about how warm and cozy domestic life is and they want a slice of it. Leaving your windows open at different times of the day will attract different kinds of critters, but you probably don’t want any. Something like a cat screen will let you keep cool and stay bug-free.
You’re a fan of antique furniture

Anything that’s old and made of wood – so chairs, trunks, cabinets and haunted dolls – all risk bringing in unwanted visitors. The doll is a red herring; they all contain spirits, but they could also harbour mites and bedbugs. Silverfish have also been known to lay eggs in books, so dust off those second-hand classics you’re never going to read.
Your neighbours are getting fumigated

The good news is that if you do spot any infestations, you’re probably not alone. The bad news is that you live in a community and, in exchange, your neighbour’s bugs are your bugs. Swarm insects all act differently, some of them will limit their numbers in one location, while others won’t mind crossing the road and piling into your windowsill like a clown car.
You travel often

Bed bugs aren’t shy about mattress hopping. In fact, they’re pretty incredible at it! They can latch onto clothes and bags and make their way from hostels and hotels to trains and aeroplanes, making multiple layovers without a single complaint before reaching their final destination of your comfy mattress.
Your packages arrive pre-digested

A lot of animals really like playing with cardboard. It’s not often they come across such pliable wood in the wild, so everything from a dog to a howler monkey will sit and chew on cardboard given the chance. That makes the cardboard you have sitting on your porch, in your garage, or up the attic a good barometer for measuring the concentration of hungry vermin.
You never vacuum

Fleas and their offspring aren’t the only bugs that enjoy living among the carpet fibres. As mentioned, bugs evolve fast, so we get critters that are delightfully named after human inventions like the carpet bug and the carpet moth, and you can guess where that comes from. They lay eggs deep in the material and can look like maggots from afar.
You don’t brush up after cooking

The laws of thermodynamics teach us that smaller animals have a much greater surface area compared to their volume, so they lose a lot of energy in the form of endothermic reactions. That’s why they’re so resourceful and good at finding food because they have to be! That means any easy crumbs you leave on the floor are guaranteed to attract the hordes.
You don’t clear cupboards

Similar to carpets, cupboards are not only excellent sources of food but also darkness and warmth. The back panels are often thinner wood and easy to chew through, and any below the counter can be connected from behind, so they have an easy time getting in and out. Clear away any spilt spices or cookie crumbs to stave off the rats and marsupials.
Grease streaks

Rats and mice are great at solving mazes, which we know by now and so we should probably stop building labyrinths for rodents. Once they find a safe path from A to B, they commit it to memory and will travel it daily, which means you’ll see a residual build-up of whatever muck or grease they carry in with them along their route.
You only see one type of bug

A house is its own self-contained ecosystem. Every ant and spider you see are travelling their relative cross-country treks, learning and evolving by the day as they live semi-symbiotically with humanity. Variety is the sign of a healthy biosphere so, if you notice an abundance of one particular insect, that’s a sign something has shifted and allowed them to increase their population.
You notice strange smells

Odour seems like a strange way to try and identify infestations, but insects and vermin are known to emit vapour that we can detect. Rats and mice have been known to smell like ammonia, a chemical present in urine and other nitrogen-filled waste of some creatures. Roaches are said to have an oilier, more umami/savoury smell, though in no way appetizing.
The house has a history of bug infestation

If at all possible, it’s worth contacting former tenants, property managers or landlords to ask about any complaints in the past. Fresh movers expect a little bit of peeling paint, some sawdust and clutter while they settle in, but it’s worth checking those are wear and tear – not a sign of bug damage.
The grass around your house is damaged

This is a fairly obvious sign that often goes unnoticed. Invest in a magnifying glass if you want to live the entomological fantasy, but you don’t need one to spot when your lawn has been grazed on by some hungry caterpillars. Check beneath your windowsills, around pipes and near any entrances for distinctive holes or tiny teeth marks.
Your garden gets mole-hills

This is a good sign for you because it means bugs are abundant in the area, but the appropriate authorities are on the case. Moles aren’t blind, they have basic eyesight geared towards detecting shifts in light, and that’s all they need to vacuum up bugs, worms and larvae. Leave these expert eradicators in peace when they clock into your garden.
You see a cockroach

If you’re a fan of Kitchen Nightmares, you’re probably conditioned to hear the editing sound effect sting and that shrill sound effect when you read ‘cockroach’. That’s a reputation they deserve though, they carry harmful bacteria and spread it everywhere. Seeing just one cockroach is a sign there they probably have many friends in the area.
You have older windows

While original windows are always going to have an appeal over the standard PVC double-glazing, they are much more susceptible to the environment. Wood is porous and reactive, it expands and contracts with temperature and humidity, and while it will still be perfectly functional as a window, the gaps that form over time are portals into your home for bugs.
You have roof damage

Mostly all household bugs and pests are expert climbers, and that involves rats and mice. They can scale trees and certain walls quite easily, so any open chimneys or loose slats can be a point of entry. Roofs are an investment, so be sure to invest in good weatherproofing if you can, and trim any branches that reach over it.
Your pet seems fixated on small holes

This one can be tricky since dogs and cats stare at walls sometimes for seemingly no reason. Often though, they might become excited by small crevices, trying to claw or squeeze their faces in, and this can be a sign there is something they smell or hear in there they want to hunt. It doesn’t necessarily mean mice, cats do also hunt bugs.
You don’t trash your leaves

As autumn arrives, the branches shed their coats and the temperature drops, which creates both an incentive for animals to seek shelter and a means for it. Large piles of leaves and mulch are the perfect temporary accommodations for all kinds of creatures as they capture more territory and prepare to lay siege to your house.
You find yellow stains on paper

Yellowing in old books is natural, it is usually caused by the oxidization of the ink or any preservation treatments over time – but your printer-warm tax returns should stay white for a while. Yellow stains on any paper there clearly shouldn’t be are the remnants of silverfish, who feed on the starches and sugars that stand between you and the IRS knocking at your door.
You don’t throw away fruit

We should all be eating more fresh fruit, and knowing how and where to store each one will help you get the most out of them. Leaving them all together speeds up decomposition as their vapours interact and create new reactions, which is an irresistible scent for fruit flies. They’re drawn to the fructose and will multiply before you even notice.
You have stagnant water near your home

Stagnant water pools are the perfect breeding ground for all kinds of nasty bacteria and other micro-organisms, and they’re also the favoured nesting spot of mosquitos. It only takes one to ruin your day, and an infestation would be a huge health hazard, so check around gutters after heavy rain or storms to make sure there is no flooding.
You wake up with bite marks

Getting a couple over the summer is very common, especially for those who work outdoors, waking up with fresh ones is a sign you could be infested already. Most insects are active at night, but the most common culprits would be bed bugs, mites, or fleas if you have an animal that likes to sleep on the bed.
Your clothes are damaged

This is the age-old calling card of the moth. Silk, wool, and any natural fibre commonly found in clothes are a moth’s primary food source, and your Egyptian cotton pyjamas are their fillet mignon. Vacuuming inside your closet and any other dark corners can help, as can moth balls and keeping your clothes clean.