I use leather treatment every 4 months or so.
I live in So Cal so it gets hot, but never so hot that I will burn my ass off.
If you have leather, enjoy it, I always say.
My dad always had seat covers on his car growing up and Id say, dad, this is nice leather, why not enjoy it, he just said shut up and get in.
Then the car was stolen, LOL, the seats were the nicest parts to the car.
Anyhow, I know from past sales experience that if you want to get your seats recovered, the dealer charges usually 1000 to cover cloth seats with high end leather if that is a aftermarket option you want on your car.
So figure if you find out which companies reupholster seats for dealerships, just go to them directly and save yourself 500 bucks.
I think teh only time you should have seat covers is when you be getting in th etruck all muddy mudskipper styles.
I grew up at the beach and we always just threw beach towels on our seats and leaned fwd on our way home.