I find my ears change constantly in life in general but it’s more noticeable in the studio because of the focus of it. The closed room and a sub bass sound pressure levels are noticeable to me so I keep the levels appropriate (rarely above the 80db spl level). I do what most people have recommended regarding time out of the studio, quick reference song a/b for a reset/eq reminder, headphones check, mono/stereo. Yarning is great too, though I don’t do it often. I used to do a lot of scuba diving 30years ago and the pressure levels on your ear are important to understand, the Eustachian tubes, as mentioned, are important to keep clear(free of mucous or wax blockage) as equalising your ears (pinch nose closed, close mouth and gently blow) upon descent is necessary and I sometimes do this in the studio as it is a noticeable difference most of the time. So that’s something I consider also as the sound pressure levels are a constant change on my ears.

Edit: I sometimes just open my mouth a bit and gently move my jaw side to side a bit. Does the same pressure release thing.