I try my best not to leave them out all year. Squirrels eat the straps, seat, and one time had so many acorns in the seat when I put it down at oh dark thrity,it sounded like 50 pounds of marbles in a garbage can.
I usually bring them in every year, inspect them, replace any susupect bolts, sand and paint any rust, and I have even replaced seats. Like any equipment, you get out of it waht you put into it.
I know one thing, I ALWAYS inspect each one before I climb on. One time I found an attachment strap literally hanging by threads...tree rats. If I had climbed aboard, it would have been a fast thirty feet to the stone wall below. Now I use chains.