Applications need to have a focus, if u apply for 100 places, you most likely is just copying pasting same personal statement/cover letter, which will reveal clearly you dont really know what u want from the position, what you can offer to them, or what your plan for ur future is -- the first thing ppl look for in an application; Also, look for a job after 6 months is a bad sign for you, only means two things, either you are not good enough for the position, or you dont really know what you need, again, reflecting your lack of clear view of your career , or your judgement capability. Better to think carefully before you apply to all the programs in your field , becoz u will apply for the same places in the future for different positions and you dont want to be remembered as a desperate person w/o a clear career goal .... Good luck!