The most obvious difference between single-, double- and triple-blade razors is the number of blades in the razor. Though the number of blades on widely sold razors has steadily increased since the 1980s, most sources agree that fewer blades may actually produce a better shave.
With blade numbers consistently increasing on mainstream razor brands, the market shows a predisposition toward the "more blades, better shave" mentality. Advertisements tout multi-blade cutting action and a closer shave for the customer. However, another faction of consumers argue that shaving with added blades may result in an inferior shave. Rather than adapting to the invention of a superior product, the market's transition to more blades is a consequence of the profit-driven switch from reusable, durable, one-bladed razors of the past to the disposable, multi-bladed razors sold in modern drugstores.
Using a razor with too many blades can be irritating to the skin; the space between multiple blades is too tiny to cut all the hairs in one pass over the skin, forcing users of multi-blade razors to shave over the same spot many times. The blades also end up cutting the hair beneath the surface of the skin, so while these razors do technically give the user a closer shave, they are also more likely to give the user ingrown hairs.