Experts also reveal the type of pillow you should buy depending on your sleep position.
A lot of us struggle with sleep issues at different points in our lives but we don't often think to look at our own pillows as the possible cause for the problem.
If you're having trouble sleeping, there are a couple of very simple tests you can do to see if your pillow is responsible for the issue.
The saddlebag test
Lay your pillow over your arm. If you can fold it in half over your arm, it's time to go pillow shopping.
If you can't easily fold the pillow, then keep using it.
The press test
Place your pillow on a firm surface, such as a table, and press down the middle.
Does it loft back into shape when you remove your hand? Then it's still good to use.
If the pillow stays flat after you remove your hand, it's time to replace it.
The simple tests have been shared by the experts at the Tielle Love Luxury's pillow swap programme in the UK, according to the Daily Mail.
They've also explained that the type of pillow you should purchase depends on what position you normally prefer to sleep in.
People who like to sleep on their back should choose a soft pillow that won't put a lot of stress on the neck.
Those who prefer to sleep on their side need a higher and firmer pillow, to keep their neck aligned with their spine.
If you toss and turn a lot, you should go with a medium height pillow.