Just the basics, really.
As you’re laying on a mattress, ask about its materials. Is it memory foam, latex, springs, hybrid? See if you can ask about specifics, if you like a feel of a mattress. Is it 6" of coils, 4" of soft memory foam? All latex, ranging from firm to soft? Dunlop latex? Talalay? The more information you have, the better armed you are to make a decision. So fine, you learn that the mattress you find most comfortable is let’s say a latex hybrid, 8" coils, with 3" medium Dunlop, then 2" soft Dunlop on top. Now you have a starting point. You can try similar mattresses in other locations, see if they match up to your expectations. You can try one with firm Dunlop in the middle, or medium on top, and see how that compares - better or worse? And that will help you start narrowing things down to what feels good for you. Soft and firm and all those other terms are SO subjective. Even if they can tell you on a scale of 1-10, the numbers have a good bit of wiggle room. So it helps to spend time just laying on beds and seeing what feels good, at least initially, vs what immediately feels off.
If you can ask the salesperson to take a look at your back and check your spinal alignment, that’s a good idea. There are charts you can check for yourself before you go, but obviously you can’t see your own back! But basically, if you’re laying on your side, you want your spine to be in a straight line from your neck to your bottom. You want your hips to sink in a bit, but not so much that your spine droops below that straight line. You want your shoulders cradled too, but same thing. And ideally, you want a pillow while you’re testing that holds your neck straight, too. You can do similar checks on your own if you’re laying on your back - does the mattress curve up to support the small of your back? Try to slide your hand between the mattress and the small of your back. If they’re touching, great. If there’s an open gap, not great. But on your side, you’ll need to ask the salesperson to help you check!
I don’t know what you’ll end up needing to prioritize, but I can tell you what I asked about at various places (including here!) -
I sleep hot. Like, surface of the sun hot. It’s awful. And I always have, even as an infant. So I have a long history of insomnia, in part because of how hot I run. I’ve learned over the years that for me, anything that claims to have some high-tech “cooling” fabric is a lie. Sure, it might feel cool at first, but once I’ve laid on it a bit, the tech gets overwhelmed by my body heat and just holds it around me and reflects it right back at me. I bake. I fry. I sweat. It’s not pretty. For me, natural materials have been proving to be the answer. No polyester or microfiber or other plasticky material. And definitely no memory foam, which allows you to sink in and basically makes me marinate in my heat. I knew I wanted latex, maybe coils, wool, cotton. That’s it.
So I asked to see latex and latex hybrid mattresses. Then I asked about the encasement fabric - one lovely, $6k-ish mattress I laid on was covered in a polyblend encasement. No good for me. I asked about the firmness levels of the overall mattress, as well as the different layers within. I asked for the height and ILDs of the latex layers (that’s the density level of the latex foam), where they were willing to give them to me. I asked what was used in the fireproofing layers - usually with latex, it’s wool, which is lovely and comfy and naturally fireproof. In some other mattresses, it’s things like fiberglass, which gets a no thanks from me.
I asked about trial periods, returns, and exchanges, and if there’s any adjustments that could be made if the mattress wasn’t totally wrong for me, but also wasn’t totally right. I asked about toppers I could add - and what they were made of. Same showroom, the really helpful guy (no sarcasm, he was super helpful, and I think trying to save me money) kept trying to convince me that topping that expensive all-latex mattress with a 1" topper made of synthetic foam and fabric would keep me cooler. Nope, no thanks, not for me. That showroom showed my husband, to his serious surprise, that he vastly preferred all-latex to a latex/coil hybrid. I liked both equally, so we moved forward looking at all latex from that point…
I also asked about what kind of base the various mattresses needed to sit on. And eventually, about adjustable beds to pair with the mattresses, as my husband realized wanted to add that on as well. We tested different brands and different abilities of the adjustable frames. Again, my husband discovered a strong preference for a particular feature, so we then knew to keep asking for that as we went elsewhere. It allowed us to compare apples to apples, so to speak, knowing what features we “need” and what we can take or leave.
I asked the salesperson to check my alignment on every bed I lay on, as I’m mostly a side sleeper. I didn’t lay on any particular bed long enough to notice pressure points or pain unless it was way too firm for me, but in one shop, the owner was able to guide me off one mattress that felt comfy to me initially, and over to another because he saw my hips were out of alignment - which I didn’t notice in the store, but would have realized over months of sleeping as my lowe back pain got worse. The one he brought me to was perfect, and was the favorite for both my husband and me in that store.
I then came here armed with what I knew my husband and I had liked - the height and density of the various layers, the type of latex, etc. I asked more questions about what the companies that are active here would recommend in my situation. I got some answers. Shopped around a bit more online to compare prices and see who could make me a similar bed at what price, and wound up going for a split king (so technically 2 mattresses) from Sleep EZ, with the setup they recommended here on this forum for my husband and I, which was based on our heights, weights, sleeping positions, and the details I was able to give from that favorite mattress we tested in person. They also can adjust the mattress (it comes in a zippered encasement) by sending out different layers if the comfort isn’t quite right. And the price was close to half of the more “reasonable” local manufacturer’s showroom, and less than half that of that latex mattress with the poly cover. It was a no-brainer. My mattresses are due to arrive tomorrow, the adjustable beds early next week, and I can’t wait to get it all set up and see how it feels. I’m happy giving it time as I adjust to the new sleeping surface, making an adjustment if necessary, adding a topper… I know it might not be perfect right out of the box. But it’s gotta be better than the sunken-in, flaming hot hellmouth I’m literally laying on right now, not sleeping.
Sorry, that turned out to be more than just the questions. I guess I’m kinda torqued up about the whole process of finding a mattress - I did a lot of research here and elsewhere, and visited 4 different manufacturers in person. I didn’t go to a big box store with mattresses or to the ubiquitous Mattress Firm because I’d already established I wanted natural materials and those are harder to find at those locations. There’s so much info to take in, and it’s so hard to compare when different companies use different terminology and their own proprietary naming and such. Take your time gathering the info you need. Figure out what feels good for your body. Then compare similar options and see what feels best. Then take it from there.