I've snapped one bass string in 25 years, and that was at home practising.
I always take a backup bass to gigs though. Currently, my gigging back up is a dirt cheap, 30” Encore! I dont have to bother taking good care of it so its propped up somewhere behind the backline or in the car if its a cramped stage.
It's not a patch on my Fender P but it would be adequate to get through a gig.
I've recently been taking an old PA head along too, as a back up for our proper PA, guitar or bass amps. Again, it'd be adequate if needed.