I'm convinced that non-hobby DE is a huge money-saver. And, of course, hobbies aren't intended to save money.
But if you avoid acquisition disorders and the hobby side of it, DE can save upwards of a dollar per-shave, often a dollar per-day.
A can of goo at the grocery store costs about $3 and delivers about 20 shaves; that's 15 cents per-shave for lather. A cake of good soap may cost $15, but can deliver 150 shaves; that, ten cents per-shave. So, on lather alone, the DE shaver saves five cents per-shave. Five cents may not seem like much, but that is $0.05 per-day and adds up. It's $18 per-year.
Multi-blade cartridges cost about $20 for a package of four, which is five dollars each. Most guys get about seven shaves, a week, from a typical cartridge (your actual results will depend on your beard). That's 71 cents per shave. This doesn't seem like such a big expense, but, again, it adds up day-after-day. It's about $260 per-year!
BIC Chrome-Platinum DE blades are $20 for 100 blades, 20 cents per-blade. I get six great shaves from a BIC Chrome-Platinum blade, typically. That's about 3 cents per-shave. And that's a 68-cent per-day savings which adds up to almost $250 per-year. And that ain't chicken's feed.
DE shaving can save a guy about $270 per-year!
If you buy a $75 razor, a $100 brush, a $25 bowl, and a $20 stand -- a very deluxe setup -- that's a $220 initial cost. But, it pays for itself in less than one year. With very minimal care, the razor, bowl, and stand will last for decades, probably a lifetime. The brush will need a new knot maybe every ten years, but that is about a $25 project.
But spending $220 for a setup is not necessary. There are great razors in the $25 price range and great brushes in the $50 range and nice stands in the $10 range and you've probably got a bowl in your kitchen that you can repurpose. You can get a great setup for well-under $100. And that $100 investment pays for itself in four or five months and you will still save $150 in the first year and then $270/year thereafter.
But even $100 for start-up isn't necessary. You can get a perfectly-adequate setup for less than $50.
This $270/year is real savings. But it can be hard to see because it accumulates slowly. Nobody just hands you a check for $270. Instead, your grocery bill goes down about $30 per-month because you are not buying another package of blades and more cans of lather. Slowly, it adds up. This is why I say that DE is the thinking man's way to shave.