Rolex watches that run with more or less effort

[daysky1]

I have several Rolex watches that I've purchased over the past 3 to 5 years. Some of them as soon as I pick them up out of the safe they start to run others I can have them on my wrist without winding them for a good couple of hours and they don't start running until after I take them off my wrist and wind them up. Why is it that some Rolex watches seem to start running with much less effort than others. Now all of these watches were brand new so the age of the watch I wouldn't think would be a factor in this but something is. I had the owner of an authorized dealer go to his safe and pull out of pre Daytona Daytona and just from him taking it out of the safe and bringing it up to the sales floor to show to me it started to run so age doesn't seem to be a factor.