[structural]

There's a lot of maintenance that is much easier/cheaper to do when the apartment is unoccupied, so the default is "do nothing, then when the tenant moves out in a year or two, do a couple years of maintenance much more affordably."

With your gym, for example, when it's new, you can do all the work you want. Once people are using it every day (especially if it's a 24/7 facility!) how exactly do you get in to do major work without making a bunch of people annoyed that half the gym is out of service for three weeks? You don't, until it gets to the point that people would prefer the downtime ... and this takes a surprising amount of grime.

[onaclov2000]

That's a good point I hadn't thought of. Large scale "projects" like that are much easier sans humanoids.