One issue that can be important when looking at prospective fitness centres is that of personal security. Of course, if you're a twenty stone body builder who works out during the day at a friendly gym in a leafy suburb, personal security may not matter much, but for others there are points to consider.
One area that can be of concern, particularly for women, is the locker rooms. They need to be well lit, preferably busy, and regularly checked by staff members. If you have any concerns about your personal security in the locker rooms then you should immediately talk to a member of staff.
Another consideration is the part of town where the club is located. Is this an area that you usually visit, or are familiar with? Is it an area that has a bad reputation? There may be a reason that a gym is cheap.
Safe parking is crucial. If you have to park on the street at night, or in a remote, unlit car park, then this is something to bear in mind. Similarly, the lighting around the club will affect the safety. Research shows that good lighting is one of the strongest deterrents to criminals.
Within the club, staff levels will affect your safety. When you are exercising it's best to have staff around. Anyone lifting heavy weights needs to have a spotter either directly watching them (for example on heavy bench press), or at least nearby should you get into difficulties.
And for women, it is more reassuring in a gym full of men if there are staff present.