with proper care anything will last. i take great care of my fishing stuff. I have an 11 year old quantum that works as good as when it was new, if not better!
Matters on how much you use it.
3 of us bought the same Diawa spinning reels when rear drag first came out in the early 80's.
2 of us fished between 3 and 6 days a week.
The third 3 times a summer. His reel is still doing fine AFAIK.
Ours flat wore out in 2 summers... the gear train wore.
Granted they weren't high end reels, but you get the idea.
I also had 2 Ryobi low profile bait casters that replaced the above spinning reel.
They lasted longer, but got all kinds of sloppy in the gear train over time.
One vibrated so much it'd put my hand "to sleep" if I fished spinnerbaits with it more than an hour.
Mid 80's brought along a pair of Abu 5600's for saltwater use.
They are still going strong. Throwing 1-2 oz lures and catching stripers up to 40"
You really do get what you pay for.
I'm meticulous in my care for my gear.
But pot metal and plastic gears will wear with use.