As with many products - it depends exactly what you have, and how its used. If you asked someone "how long does a Chevy last" they might tell you if they were happy based upon their personal experience, but how they use their car matters most.
If its a standard do they routinely redline it? Some watch movements are really sensitive to over-winding - theres a parallel there. Do they change the oil when dirty or just pour in more? Do they run it of-road? In the city? Highway? Knock it around? Baby it? Similarly you might beat the hell out of a watch, and someone like me might be gentle and rotate it with 40 other watches so it looks just as good after 10 years as it did when it arrived. And how tolerant are they of "little issues"? Some people let little things add up then one day it just bursts into flames. Other people fix whats broke the week it breaks. Its when you have a cascade of little problems that most people decide to get rid of a watch or a car.
Me? I drive a 1997 Suburban that has close to 300k miles but I fix everything as it comes up so it runs like a new car. I treat most watches that way too.
Anyway, all that aside, Asian clone movements are not as nicely built as the gens. And the price reflects that. In fact many of the movements are so cheap that they are considered throw-away. You don't repair many of them - you just buy a new movement on eBay for $30 and have your repair dude slap it in. Thats what I'd do with most of my reps. But there are exceptions - the ones I've fallen in love with. With those I'll run the Asian clone into the ground, then buy a gen ETA off eBay and put that in the clone case - and have something that will last a lifetime. But I'll need to periodically clean and lube that gen movement and thats not cheap.
Thats one of the main reasons I got into reps to begin with. To avoid repair gen costs. For what it would cost me to maintain a gen Rolex or Omega every few years I can buy a really nice rep and toss it in the trash if I wanted to when it stops - and I'll still be ahead of the game.
Your question might seem simple on the surface - but its really rather complex.