For most men, shaving is one of those daily necessities. Unless you're growing a beard, it's not something you can exactly skip.

But the automatic nature of shaving can also allow costs to sneak up. I recently conducted an experiment to see how many shaves I could get out of a middle-of-the-road razor, the Gillette Mach 3, and have compared those costs to those using an old-fashioned safety razor.

The results may shock you: Shaving the old-fashioned way, with your dad's old safety razor and a double-edged blade, is just as effective and will cost anywhere from one-fourth to one-eighth what you are paying now.

Many men use disposable razors and have for years. Gillette, the world leader in male grooming products, discontinued old-fashioned safety razors in the early 1970s, around the same time it introduced the twin-blade Trac II.

"We like to say that 800 million men around the world start their day with a Gillette product," said Mike Norton, spokesman for male grooming for Procter & Gamble, which bought Gillette in 2005. Many begin with single-blade disposables, then move up to multi-blade "system" razors with replaceable cartridges.

Eighty percent of men in North America shave with a blade and razor, while 20 percent use an electric razor.

Companies also roll out new products all the time, with new functions. Some razors emanate moisturizer. Others vibrate.

Switching up inventory keeps us interested.

"To a certain extent, customers get bored with their purchases," said Angeline Close, an assistant professor of marketing at the University of Texas at Austin. "You might be loyal to a brand like Gillette or a product like the Mach 3, but every so often you need a change."

But in recent years, the public has seemed nostalgic for shaving techniques of generations past.

A so-called wet shaving revival is taking place, with websites like thesuper­iorshave.com and amazingshaving.com selling lines of straight razors and safety razors — not to mention countless brushes, bowls, oils and creams.

I set out to answer this question: What is the most economical method of shaving? I define an "economical" shave as one that does the job effectively and at the lowest cost.

Cost per blade of a system razor

I picked the Mach 3 because it was the razor I had been using lately, and it seemed like a decent representative of a system razor. I paid $10.99 for a package of three of the razors at CVS. I then set about seeing how long each one lasted, recording each shave in a journal.

It came to 56 shaves. I ditched the first one after shave 14, feeling at the time that I had wrung out every last bit of usefulness.

I stuck it out a bit longer with the next razor and got 22 shaves. By now it had become apparent that quality was dropping in stages of three to four shaves. I found that I could physically shave my face many more times than was comfortable or enjoyable. The pattern repeated itself with the third razor, which I quit after 20 shaves.

How much did that cost?

I'll begin with a subjective assessment that a single Mach 3 cartridge was good for 10 reasonably comfortable shaves. (Even this is generous, since the feeling that something was amiss began at around shave number six.) A razor goes for $3.66 each, and I found replacement cartridges for as low as $2.08.

Let's assume (unrealistically in my case, because I've never held onto them) that you will somehow keep those three plastic razor handles forever and only buy replacement cartridges. If one cartridge lasts 10 shaves, that comes to 20.8 cents per shave (or 10.4 cents, if you don't care about comfort and can make it to 20 shaves).

Compare that with the cost of shaving with a standard safety razor and double-edged blades. I found safety razors for as little as $15 online, but they generally range from $30 to $80.

You can buy blades online from places like Japan, Germany and Turkey. I found a package of Derby DE blades from Amazon, 100 for $7.82 plus $4.98 shipping — or 12.8 cents a blade. At the other end of the scale, the well-regarded German Merkur blades run $53 for 100 on thesuperiorshave.com, or 53 cents a blade before shipping. (Chances are, you will have a hard time finding either safety razors or double-edged blades in drugstores or grocery stores. I inquired at several and could not).

The safety razor's benefits

Now the question: How much does it cost to shave with an old-fashioned safety razor?

For this, I turned to an expert.

Mark Herro, known as Mantic59 on YouTube or the Sharpologist on his blog, has done a long study on shaving. Since 2006, the telecommunications worker at Texas A&M University has put out instructional videos which have been watched 5.5 million times on YouTube. Herro, 53, contends that multi-bladed systems are "largely unnecessary" substitutes for shaving skillfully. In return for using three, four or five blades at a time, he argued, "You pay more and more for an increased efficiency you may not even notice."

He buys double-edged blades online at a cost of 17 cents a blade. He goes through one blade a week before he has to replace it.

For a seven-day week, that's 2.4 cents a shave.

Compared with my 20.8 cents per shave with the Mach 3, that's more than eight times what Herro is spending with his old-fashioned system. Grinding out 20, mostly uncomfortable shaves with the Mach 3 makes it only four times as expensive as shaving with a safety razor.

I am not claiming my test of the Mach 3 is somehow definitive. I started a similar experiment with the five-blade Fusion, Gillette's most popular razor. It lasted a bit longer — but also costs a little more.

Safety razors do mean higher start-up costs. But if you are saving anywhere close to 18 cents a shave, that pays for a $50 chrome safety razor within 10 months.

So if you're looking for the best shaves for the least amount of money, go old-fashioned and get a safety razor. You might get nicked in the process, but at least you won't get burned.

Times researcher Carolyn Edds contributed to this report. Andrew Meacham can be reached at ameacham@tampabay.com or (727) 892-2248.