I wear a wristwatch on the left wrist, Tried it on the right briefly "just to see" and found it awkward (probably a result of scores of years on the left). The things- from releases on bands (though of course the band can be reversed) to winding/hand setting stems- are all designed for LH placement.
I wear the watch pretty much all the time, to include when sleeping. My sordid background in the Army (34 years) made me very conscious of needing to be aware of just what time it was constantly. That no longer applies of course, but old habits die hard.
I am, as it happens, about 6'3" and have fairly long fingers, and very long slender hands -from wrist to knuckles. The upshot is that when I play almost any accordion the watch doesn't touch the bass strap. The exceptions are the old Excelsior 160 bass, and the Morino with the three rows of chromatic LH bass above the normal stradella rows. On both those I take off the watch. Since I like the watch snug and have a metal band, when I put it on the RH wrist it is too tight.
The 140 bass models are right on the edge, but generally OK.
If I consistently spent time on the Morino or the Excelsior as my primary instruments I'd adjust things and wear the watch on the right.
Given my dismal vision, I generally play by ear/memory these days. I'd need a 47" flat screen monitor to read music off while playing the accordion. On the piano, music under a bright light on the rack of the piano is the only printed music I really use while playing these days. When I pick up music for an accordion I generally sit down and read through it while humming it to myself and then, after I've digested it, put it down and try it on the accordion.* Same same for fake books.
* FWIW, lest anybody think I am claiming some modicum of talent- I'm not. The read it off the music/ hum it/ play it method works up to about a Palmer Hughes level 5 degree of difficulty. The Gallarini Frosini Deiro more serious pieces require- for me at least- playing off the printed music which I am increasingly unwilling to do on other than the piano (or clarinet/flute which weigh a lot less and so are easier to handle while peering at music- one note line music at that).