Depends on the gig;
anywhere from 2 to 5: Tele-Strat-LP-Acoustic-Ric 12 depending on staging and set lists.
Minimum would be 2...a Tele and Acoustic.
I've found, over the years, that a Telecaster can do it all. (So can a Strat or Les Paul). However I prefer the Tele.
If musicians ran the world there would be no wars...just an occasional battle of the bands.