I’m 3 years in with mine and I do my best to remove them and clean and treat the leather annually. I pulled the front seats completely out of the cruiser last year to clean underneath the seats and interior. The leather looks great. The back seats have to survive my now 7 and 8 year old boys. Most of their mess is caught by the seat covers or the
seat protectors their car seats sit in.
I would find a good leather conditioner and apply it at least annually. I have not pulled mine off yet this year, I’m a little behind, but if I do and I find a problem I’ll report back.
Also, there is a long thread on these covers on this forum that may have some info on leather treatments. Also, you’ll likely run into difficulties installing the front seat bottom, there’s plenty of insider info in that thread that will save your knuckles.