My only failing is packs and panniers. I have the same problem with camera bags...own several. Don't need them all, but I can't resist.
I wouldn't be able to estimate my bike expenses per year. I'd guess for maintenance and repairs, less than $100.00/year. I just mounted all new tires on three of five bikes, but mainly because two haven't been riden in so long that the tires dry-rotted (one was my dad's old Raleigh 3spd). One only new tires because one split after running over a thorn...big thorn and I wanted the tires to match. Basic maintenance I do myself.