>but shaving with 4-blade cartridge designed for easy shaving is still 'miles' ahead compared to shaving with double-edged razor
What is/are the things you prefer with the cartridge? For me, I switched to the double edge a long time ago, and didn't really notice a whole lot of difference in what it does, but a big difference in price. I keep a cartridge for getting under my nose, but doesn't need to be replaced very often. For everything else I really don't notice a difference in shaving. I don't shave every day, so my razor tends to get clogged, and the double edged can be disassembled and cleaned in a couple of seconds while shaving. The cartridges can't really be cleaned out at all which leads to premature replacement and costing a lot more $$. Even when I did shave every day, I found I would try to suck every dime out of the cartridge, so I'd end up using a worse blade anyway.
I actually tried switching to a straight razor. Found it requires a lot more skill than I'm willing to put in to learning. But it appeals to me as the ultimate in reusability.
The double edged safety razor is amazing for thicker facial hair. Even if I’m shaving every day, cartridge razors all get clogged on me. No amount of hot water gets it out, and the stuck hair roughs up my face like sandpaper.
The double edge safety razor is so much easier to clean out.
I actually tried switching to a straight razor. Found it requires a lot more skill than I'm willing to put in to learning. But it appeals to me as the ultimate in reusability.