Human: I've been thinking about buying a new mattress but I'm not sure what to look for. What are the most important things to look for? Assistant: 

1. Comfort is key when it comes to choosing a mattress.
2. Look at the density of the foam, as well as the type of foam used in the mattress.
3. Consider the thickness of the mattress and how it will support your body weight.
4. Take note of the warranty included with the mattress.
5. Check out customer reviews to get an idea of how the mattress performs.