Hi there -- We can actually do even better than an educated guess in this case, since we've actually done some pertinent fatigue testing here, which simulates 10 years of use. The answer here will actually depend on your weight. Can you give me a rough idea of how much you weigh?

Also, FWIW, we found the ProAdapt Medium to have the same softness level as the Adapt Medium, with slightly less cushioning depth. The hybrid versions, as you probably already found, are a little softer. I created a comparison of all the mediums in the Adapt collection for you here:

https://www.goodbed.com/compare/?mod=tempur-adapt-medium&mod=tempur-adapt-medium-hybrid&mod=tempur-pedic-medium-1&mod=tempur-proadapt-medium-hybrid&mod=tempur-luxeadapt-medium-hybrid

I hope that's helpful.

Thanks for the prompt response! That would match up with our findings as we definitely felt the hybrid model to have too much sinkage or cushioning depth for our tastes. I am 6'0", 200lbs and my girlfriend is 5'10, 155lbs while both having "athletic" build types.

In that case, it sounds like it may be worthwhile finding a local retailer that has a ProAdapt medium on display to test against the Adapt medium and ProAdapt firm as we do prefer that less sinkage or cushioning depth feeling.

I'll check out your provided comparison link in the meantime and look forward to hearing about your fatigue testing based upon our weights!

OK, sounds good. In your case I wouldn't expect the cushioning depth on these T-P models to change more than 1/4" during that time frame. Is that helpful for you?

Thanks! Sounds like if it's generally only a 1/4" more depression or softening and not something like 1/2-3/4", then the firm would probably still be too hard for my weight during side sleeping.

Yeah, if you were looking at only the difference in cushioning depth, those two models aren't that far apart to start with, so it's possible the Firm could get close to the Medium. But on Softness, they are much further apart. So if you're looking for its softness to change in order to aid with pressure relief when side sleeping, I don't think it's going to get anywhere close to the Medium on that front.