If you want your tack to last, you take care of it properly.
Not being rich, it's less expensive for me to take the time to maintain my leather tack, than it would be to replace it because it dry rotted.
I've had one bridle for over 25 years now, and it looks better than the day I bought it.
I also have an old leather saddleseat saddle that I don't use anymore, but it gets cleaned every several months and deep oiled once a year. It's in excellent condition, and I rode in that sucker a LOT.
My Wintec gets cleaned after every ride too, although no oiling. I bought my 2000 AP 6 or 7 years ago, and it still looks brand new.
My horses always get groomed before a ride, and groomed and bathed (weather permitting) after each ride. I also keep their bridle paths, facial whiskers, and fetlocks clipped.
I'm going to assume all of this is because of my show riding training. Unless the horse, tack, and rider are all impeccably groomed, they're not to go out in public. Even for a backyard trail ride.