The dexterity and focus required also means Reuben must test his body daily, pushing himself to his limits inside a sauna before swimming laps in an Olympic pool to condition himself.
George Daniels was a cigar-smoking, claret-drinking, Rolls-Royce driving dandy and the idea that ZOMFG you have to swim laps and sweat lodge before you can hold a riffler file is pretty hilarious.
Bummer that the dude gave himself leishmaniasis or whatever buuuuut most of the watchmaking schools require you to make a movement by hand that "ticks." They're all ugly, much like this one. At least if you buy some of Daniels' books you get templates and instructions.
What George Daniels was famous for was exquisite finish. The Watchmaker's Apprentice, which you should not watch because it is excruciatingly dull, is all about how Roger Smith spent three years building a George Daniels watch only to take it to George and be told it was fuggly and the finish was awful so he had to go back and build another George Daniels watch which took like six years except this time it was pretty so George puffed on his cigar and said "Smith old boy you will be my galley slave for the next fifteen years" and now that George is very dead people pay $300k for one of the ten or so watches Roger Smith and his workshop of like eight people make every year.
Note that George Daniels made like 23 watches his entire life. They're very impressive, but he's the patron saint of the Godly Watchmaker school of mechanics. He's famous for the coaxial escapement, which was supposed to not require lubrication, which Omega bought, which has a lubrication table, and which is a complication on some watches like a tourbillon or whatever.
This is Clickspring. Think he's Australian. He does handmade clocks'n'shit with exquisite finishes up on like Youtube. I'm lazy? I prefer my shit mechanized? But I gotta respect it. This whole "only albino monks that sit down to pee have the stamina necessary to fabricate a sweep seconds mechanism out of echidna droppings and the eyelashes of virgins" school of journalism, on the other hand...