Towel Service

Towel service is one of the first things I look at when joining a gym.  Think about it: if you go belong to a gym with towel service, it is more likely that it will be cleaner all-around because everyone has access to towel(s).  They will be more likely to wipe up their sweat/mess or somebody elses because they can always just get a new clean towel.  At a gym where people bring their own towels people might forget or not end up cleaning all their sweat off the last machine/bench/weights they just used.  Another bonus about gyms with towel service is that they allow you to just drop your towels off when you're done, meaning you don't have to bring it home and wash it yourself.  The convenience factor is huge, plus it is more likely that the gym you'll be in will be a cleaner one.