What's behind our ratings
If you are a side sleeper, you need firmness that contours the curves created by a body sleeping on one side. You also need plenty of support in order to prevent pelvic rotation.
A good mattress is not likely to be very cheap, so it should at least last for a very long time. The materials from which it is made and the warranty offered by the manufacturer are the main indicators of its durability.
Firmness and support are two different things. While all should offer a good spinal support, choosing between a hard, a medium or a soft one is more of a matter of taste.
If you are a back sleeper, you should choose a softer model which contours the arch of the lower back. We advise you to choose one which offers a good spinal support, topped with some plush padding.
If your partner is a restless sleeper, you might want to invest in motion isolation. This way, they can toss and turn all night, without disturbing your sleep.
A quality mattress should be covered by a good warranty of at least 15 years. If a manufacturer claims that it lasts for 20 years, but they only offer a 10-year warranty, then they are not very trustworthy.