I have had a string break, amps crap out, dodgy leads. At a recent gig at the start of the second set just as I pushed my lead into the input socket of the bass, the nut and washer fell off onto the floors and the socket fell inside the bass!
I turned to tell the guitarist what happened. He looked shocked and said “what are you going to do now!” I said “nothing” just smiled, leant across and grabbed my spare bass!
Pays to be prepared.