It's vital to keep your baby's cot mattress clean and germ-free, especially as your baby will be sleeping between 12 and 18 hours a day in his or her cot or cot bed during the first year.
Our tell you whether a cot mattress is easy to keep clean, how much protection it offers against night-time accidents and if you'll need to spend extra to get a waterproof protector or cot mattress cover.
We surveyed 1,008 parents in February 2019 to ask them how often they cleaned their cot mattress:
The truth is there's no hard and fast rule as to how frequently you should clean a cot mattress, except obviously making sure you get to any spills and leaks straightaway.
It's also recommended you change the cover on your cot mattress at least once or twice a week if possible.
This means it's handy to have spare covers to deal with an accident in the middle of the night, as you don't want your baby sleeping on a damp mattress.
Just under two thirds of parents we surveyed use a waterproof protector to guard their cot mattress against accidents and sickness.
It's completely optional as to whether you use one, but it's worth bearing in mind that not all mattresses are water resistant.
This means that urine can soak into the core and bacteria could fester, making it unhygienic for your baby to sleep on.
Our tests have discovered cot mattresses with a miserable one star for water resistance, but others get a great five stars.
Others have only partial waterproofing. That means it's pot luck as to whether your baby has an accident on the protected part. Or the underside is waterproof so it traps in liquid and makes it impossible to clean.
We recommend always having a non-waterproof soft top cover for your baby to sleep on, which you can whip off and machine-wash it if it gets dirty.
Some cot mattresses don't come with a washable and removable top cover, so you'll have to budget for this separately.
Others have covers that shrink after washing, making it a nightmare to put them back on the mattress. This could also pose a safety risk if the shrunken cover compresses the mattress, leaving gaps that could trap your baby between the mattress and the cot sides.