How often should you change your razor blade?

How often should you get a new razor if you shave your armpits with it every other day, and your pubis once a week?|||I change my razor every 2 weeks. It's really unsanitary to keep them longer. Keeping razors too long can cause staph.(Gross!)|||it depends on how dull it gets but i wouldnt go no longer than a week or two|||I change mine at least once a week|||every 2 weeks.|||When the moisturizing strip is ate up|||I would get one week out of my blades. Now, with only one leg to shave, the blade should go two weeks, but I still discard it after one week for sanitary reasons.