Nervous about mattress shopping

Our last mattress purchase was quite a few ago, and we thought we did our due diligence, going to various local stores, laying on lots of mattresses, going back and forth between stores to compare. And for the first year, it was very comfortable, but after a few years, both of were finding ourselves stuck in dips, having sore hips and shoulders, etc. This is despite “rotating” it periodically. We added toppers of various types, but have just not been comfortable for years. We finally decided we’ll try again. We thought we’d get one at Costco since they allow returns even after a long time has gone by. But I ran into this website, and I’ve read through the information and tutorials. I realize now that we had no idea what we’re doing and a purchase from Costco would probably just end up being returned after a while. So now I just feel super nervous that I won’t remember everything I’ve read on here and we’ll end up still making the wrong purchase and becoming uncomfortable after the return period is over.

I see one of the “trusted members” on the list, Bay Bed and Mattress, is local to me, and another, Nest, has a location about 45 minute drive from me. Bay Bed and Mattress has mostly positive yelp reviews and only a few negatives. But I’m just so nervous about messing up this purchase. We’re not the type to replace a mattress in a few years, even if it’s uncomfortable, so I want to make sure we get it right this time.

I plan to start at Bay Bed and Mattress since it’s local. Would you recommend I also make the drive to Nest in Palo Alto (45 minutes drive) to do my due diligence? My plan is visit the store, write down what the sales person says, write down details about whatever beds we try out, then come back home and come to this website to look up all the materials we tested before making a decision.

Any additional advise before we visit the store?

Stats: we are both in our 50’s, not athletes, but physically fit.
Me: 5’8, 150 lbs, weight distribution has more on my hips than my upper body, side sleeper but I change sides a lot during the night. Sore shoulders most mornings, occasionally sore hips. Soreness goes away soon after getting up and moving around, so it’s got to be the mattress.
Him: 6’, 180 lbs, even weight distribution except a bit of excess on the belly. Side sleeper (both sides), but I observe him sleeping on his back sometimes when I wake up. He has a chronic “bad back”, since childhood, so needs support, and he has mild arthritis in his hips and knees that cause pain throughout the day - not related to the mattress but the mattress seems to make the hips worse during the night.
Also on the mattress: 2 cats, typically one at our feet and one closer to our shoulder area. 13-15 lbs each.

Price range: $1500 or less preferred, but could up that a bit if we have to. We’d like the mattress to last 8-10 years.

Open to any advise about our mattress shopping to help us not make another big mistake.