The heart of almost all venues, the gym and health club facilities are what should have attracted you to the place. A gym can have all the atmosphere and ambience in the world, but if it doesn't have good facilities it won't be worth much.
The first thing to consider is the actual exercise equipment - does the gym or health club have a good selection of free-weights, resistance machines and CV equipment? Which fitness equipment matters most is a question of personal preference, so be clear what your work-out goals are, and then ensure that the club you choose has the equipment you need.
The rooms themselves are also important - are they small and dingy, hard to move around in and smelling of old trainers? Or are they clean and airy, with space to workout safely? For classes, the best gyms have large rooms with air-conditioning and sprung floors.
For those who enjoy sports, a multi-purpose hall is a must, somewhere to play basketball or badminton, or enjoy winter 5-a-side. Squash courts are still popular, and many clubs also have outside facilities such as floodlit tennis courts and all-weather football pitches.
One area that people often overlook are the changing rooms. Ideally, they will be large, clean, and with individual areas for those who like a little privacy. Secure lockers are a must, and items such as hair-dryers make a difference.
And when your workout is done, it's nice to have somewhere to pick up a healthy snack - a juice bar or caf? - or chill out in a sauna or steam room. If you like to be pampered, some clubs also have treatment and beauty rooms, so that by the time you leave the gym you look as good on the outside as you feel on the inside.