Users of straight razors will say a lifetime – but this is not the same for double edged (DE) razor blades!
Experience differs here, but a good average is to change your blade at least once a week. If you feel the blade skipping or nicking, then perhaps it is time to change it sooner.
‘How many shaves you will get out of a single razor blade can vary widely.’
The number of shaves you get from a blade is very variable. It depends on a range of factors including the number of passes you make with the blade for each shave and the nature of your hair.
Many NOS (new old stock, a vintage item that is new and used, still in its original packaging for the purists) vintage blades are widely believed to last longer than modern blades. Some of these vintage razor blades, such as the Personna 74 are described with almost magical qualities! If you search around shaving forums you will see stories of blades being used for a whole month – but this is NOT recommended.