We believe there are four things in life you should overpay for. The first three: Pillows, mattresses and their coverings. The fourth thing? A good kitchen knife (not to be used in the bed).
While there's no one standard mattress that works for everyone, you have to pick what feels right for you—and try it out with your partner if you sleep with one. But you can't judge that in 30 seconds in a store. Tell the salesperson to back off and give you 15 minutes to get the feel for a mattress before you pick it. Judge it for comfort, support and heat (you don't want heat dissipated too quickly, but a mattress pad may help).
One good option: A memory foam mattress, which bounces back to the original flat plane after you get out of bed (rather than forming an indentation). However, they can be costly—up to $2,500. Instead, you can take a standard mattress and flip it every couple months to avoid body indentations that will disrupt your sleep.
And get a 1 micron cover that blocks allergens from floating from the pillow or mattress to your nose and body.