The other thing is that bike maintenance and wear is more a question of miles than years, so a 5 year old bike that gets 1000 miles a year will likely be less worn than a year old bike that's been ridden 6000 miles. So, what kind of mileage are we talking about?

And one other thing - bicycles are mostly pretty simple machines, and pretty easy to work on with fairly inexpensive tools. I know not everyone is equally adept mechanically, and not everyone has the same level of interest in working on their bike. But if you can do it, learning how to make your own adjustments, replace your own cables, chains, cassettes, and chainrings, etc. is pretty straightforward and you'll no longer be at the mercy of whatever wrench works at whatever bike shop you can get to.