Usually takes me about 35 - 40 minutes, from inspecting the frame, removing old strings, mounting and stringing. Sometimes it's a little longer depending on the racquet. I of course am a firm believer in taking the extra time to do a quality job instead of trying to beat the clock. If one can do a quality job in 20 minutes, great. If it takes one an hour or more to do a quality job, that's fine too IMO.
By the way, I use a Laserfibre/Stringway MS200FX. It's a dropweight but is just as fast as an electric.
Former USPTA Teaching Professional - Current USRSA Member
Dunlop Max 200g Pro - Custom 14.5 oz, 9 pts HL, 47 lbs.