I'd always take two guitars. It's been years amd years since I last broke a string but I wouldn't take any chances on a gig as nothing screams 'unprofessional' more than having to stop a tune whilst I go off to re-string.
I also want access to diffrent sounds so i'd likely take my Strat and a humbucker guitar. It's been a bit since I last did a gig so when I do gig again i'd likely take my Strat and alternate between the Bernie or SEC24. Not inconceivable that the Strat may get left at home as I can use the coil tap and trem of the C24!