Talwalkars is a good organized chain of gymnasiums that offers all basic fitness equipments within a very good infrastructure.
I knew a person who owned a small gym and he told me that about 80% of the new members would pay for 12 months and drop out of the gym within first 3 months due to various reasons such as time constraints, lack of motivation, lack of results etc. Unless you are from the defense forces, exercise is mostly an optional activity and one tends to become de-motivated due to various reasons.