There is nothing like a virgin Rolex to bring out my "A" game.  

If nobody has been into it, it's a wonderful challenge to only leave the date and identification of the work behind, etched in the case back in tiny script.  Not leaving a single screw driver mark means learning and caring to sharpen ones tools well.  Not losing a screw or slipping with the tweezers is just part and parcel of the practise.  The thing is, on any given day my brain can be misled into thinking that my hands are better than they are.  The real challenge is in only going as fast as I can to perform well.  The second I get ahead of myself I can't do my best work.  

Rolex with case back open

I suppose that goes for all of us doesn't it?  I'm prone to the hyper side of ADHD so mine is a meditative practise that revolves around a deep focus where nothing remains but the work on the bench.  At least on a good day that's the way it is.  I'm human after all.  In school, studying under Joseph Rugole, we were never pressured to be at the bench, we just had to be done the assigned work at the given deadline.  When the stars are aligned and everything is right with the world the work can go very quickly.  If I lose my sense of humility, I can back peddle a long way to get back to par.
balance bridge and wheel inverted
Fortunately I didn't have to wait for delivery of a wrench of become inpatient and make one.  Dad had one handy.  Dads are tremendous folks no?  That's a half millimetre spline wrench.  Easy does it!
Rolex Micro Stella wrench
It was Rolex week last week as I had a couple of mechanically strong ones come my way for servicing.  They both have a "free sprung" balance.  Very fancy.  A free sprung balance is one more way that a manufacturer can eliminate predictable errors in timekeeping that are presented by the physics of the game.  Please refer to David Landes Revolution in Time for the big picture.
balance wheel with mean time screws
This watch has a free sprung balance has two mean time screws to regulate the timekeeping and that, only through a very narrow range.  The two splined nuts are carried on two opposing threaded posts on the inside rim of the balance wheel.  Moving the nuts toward the centre of the wheel decreases the radius of gyration and increases the rate.  Moving the splined nuts toward the balance wheel rim increases the radius of gyration and slows the rate.  Lovely adjustments for the skilled mechanic to have at his or her disposal and thanks for everything Dad. 
This image has been floating around the internet.  It's not mine.  This method will work for any well timed mechanical watch.  It provides an easy way to keep the timekeeping on a mechanical watch pretty close to the mark if it's set up well to begin with.
instructions on self regulating a watch