Although no razor manufacturer speculates as to how many shaves to expect from a razor, according to Sharpologist, disposable razors are good for about four shaves per razor. As of March 2013, this meant the cost of using disposable razors was approximately 30 cents per shave.
As of 2013, the cost of using a cartridge razor, in which one keeps the razor but replaces the blades, ranged from about 11 to 27 cents per shave. A double-edged razor cost approximately 7 cents per shave, and a straight razor cost 1 cent per shave. A disposable razor is thus 22 times more expensive to use than a straight razor and anywhere from twice as expensive to only slightly more expensive to use than a cartridge razor.
The life of a disposable razor, however, can be extended by drying the razor with a blow dryer after each use. Another way to extend it is to run it 20 times in each direction up the leg of an old pair of jeans, a procedure which both dries and sharpens the blade.
Although some disposable razors are made from recycled plastic, they are worse for the environment than cartridge, double-edged or straight razors, since most are thrown away rather than recycled. Over 2 billion disposable razors are sold in the United States yearly.