I broke a string before christmas at rehearsal, but that turned out to be a problem with the bridge, once I'd got that sorted everything's been ticket-boo. I don't take a backup bass, amp or cab. Down that route madness lies...
I've got a bass lead with an XLR plug on the other end though - the absolute worst case scenario is that I go through the 'snake' to the PA directly. Worse things happen at sea.
Also I really look after my kit.