FORTUNE -- General Motors' legendary CEO Alfred P. Sloan invented the annual styling change when he ordered a new body for the 1923 Chevrolet to cover up the car's nine-year-old technology. The new design made the old model feel out-of-date and was the first step in GM's drive to pass Ford Motor and its unchanging Model T to become the largest automobile company in the world.
The complexity of modern cars combined with government crash test regulations made annual model change obsolete by the 1980s. Today's cars are fortunate if they receive a freshening every two or three years. But systematic alterations in design to revive consumer interest have become an integral part of the American consumer economy.
As advertisers learned long ago, the two words with the greatest appeal for potential customers are "free" and "new."
The predictable model change gives sellers a chance to shout "new."
Which brings us to the Gillette Fusion ProGlide razor. Razors and cars have more in common than appears at first glance.
Both razors and cars are used on a daily basis, both are mature technologies, both are marketed primarily to men, and both are sold with sizzle along with steak.
For most of its history, Gillette made innovations to its core product at a stately, unhurried pace that seemed to suggest that a good deal of thought, planning, and hard work had gone into design changes before they were unleashed on the world.
Gillette introduced the Blue Blade, the blade dispenser, and the stainless steel blade, in 1932.
But the Trac II, the world's first twin-blade shaving cartridge , didn't make its debut until 1971.
The Sensor razor with spring-mounted blades appeared 28 years later in 1989, and the triple-bladed Mach3 followed in 1998 after an interval of nine years.
But lately, you would think razor blades are following Moore's Law. Changes are coming so quickly that they are hard to keep up with.
Gillette skipped the four-bladed cartridge and but managed to come up with the five-blade Fusion in 2005, a mere seven years after the Mach3.
The Fusion ProGlide doesn't pack more blades into a shaving cartridge or even promise a closer shave, previously the sine qua non of new razors. The new technology, according to Gillette, uses "thinner, finer blades" to glide over skin "with incredible comfort."
It is a bit like a car advertisement from the 1950s and 1960s that promises the new model will be longer, lower, and wider, but doesn't say anything about fuel economy or safety.
To be sure, Gillette supports its comfort claims by identifying half a dozen new features that contribute to this "incredible comfort." Among them are a blade stabilizer, a larger lubricating strip, and a redesigned handle. My favorite is the "Snowplow Comfort Guard," that channels excess shaving cream.
In appearance, the new ProGlide razor is very similar to the old Fusion. The dimensions are nearly identical. The handle is as bit thicker with a redesigned on/off switch on the battery-powered model, has larger grip, and it is trimmed in blue, a big improvement over the old orange.
Of course you pay more for all these changes, whether they are functional or merely cosmetic.
The new ProGlide goes for $12.99 with one cartridge, a buck more than the old Fusion. And a four pack of power cartridges goes for $17.99, a $2 bump from the Fusion power cartridges.
To get a better feel for the capabilities of the new razor, I staged a comparison test, using it to shave one side of my face while I shaved the other side with a well-broken in Fusion.
Old-style Gillette Foamy shaving cream was used in both cases. Neither the Fusion ProSeries Thermal Face Scrub or Fusion ProSeries Face Wash, which Gillette has introduced along with the new razor, was available.
The new cartridge fairly gushed lubricant and, at the finish line, it did feel smoother. According to my wife, it also produced a closer shave. The difference from the old cartridge, though was barely detectable. And I wasn't able to detect the effectiveness of the Snowplow Comfort Guide.
For those with sensitive skin, the new cartridge is probably a good idea. Personally, I doubt I will be making the upgrade.
Hopefully, consumers will still have a choice. Gillette says the old Fusion will remain available. It even says the Mach3 remains in production - providing you can find a drug store that still stocks it.
But as consumers know well, the annual design change was closely followed by planned obsolescence, which was defined more than 50 years ago as "instilling in the buyer the desire to own something a little newer, a little better, a little sooner than necessary."