Mattress maintenance and cleaning

Okay another question I wanted to ask. For reference, I have the Leesa Legend Hybrid. I keep hearing advice about rotating (thanks for that btw, gonna start since I hadn't been), protectors, general care, but at this point I don’t know for sure what really matters versus what people advise out of habit.

Things I want to know:

Is it worth vacuuming my mattress at all? If so, how often should I be doing that? I don't have any kind of protector on it for dust/hypoallergenic whatnots.

Do mattress protectors make that big of a difference if you’re not messy, sweaty, or at risk of peeing the bed?

Are there signs that a mattress isn’t being “maintained” well vs just natural aging?

I never thought much about cleaning routines or anything beyond washing my sheets and stuff, but I want to keep mine in good shape for as long as possible.

Appreciate any tips!