A harness story: but a sample of only one , so make of it what you will.........
I climbed full time in the 1980's, living on £27.?? a week, so cash was tight. I bought a new Troll harness in 1981 and it was in weekly use until 1989, and then occasionally until 1992. Rock climbing, Scottish winter and Alpine summer.
In 1986, after taking a good number of modest lead falls it sustained a 20m FF2 down Pinnacle Face on Lochnagar. This fall destroyed most of the belay though obviously not all because we lived, and indeed climbed on to finish the route. The only remaining peg was removed by hand after I'd struggled back up to the high point and worked out the crux moves.
This was day 2 of a 5 day trip so there was no question of retiring it there and then! But it looked fine so continued to be used, dates as above. It must have taken a couple of dozen lead falls after that, but nothing beyond 7m. And countless abseils.
It looked fine and performed well right to the end. If there is no visible damage failure isn't going to happen on a harness 5-10 years old that is used in the totally benign environment of a climbing wall.
Maybe modern harness aren't made so well? Thinking about the self unravelling latest Petzl caving harnesses there maybe something in that.
The best solution to the OP is to avoid climbing walls. They help you get toned up, but hold you back in all other respects when it comes to leading 'real' climbs