Apply close to when you're supposed to come and have the visit/exam. For all you know, you can be granted a multiple entry visa with 6 months validity period. So you didn't gain anything from that.
Thanks Job_seeker for quick reply
If you can clarify further,whats the actual validity period for single entry & multiple entry visit visas? As I'm going to apply for visit visa now, to book my exam in Aug.2012.If I will apply for single entry it has validity of six months,so I can't book that exam so I thought to apply for multiple entry?
If you can put light on this matter & guide me.