Thanks to the fine advise offered here, I take 2 - 1 primary and one backup. Even in my short time of gigging I've had to use the backup (strap pin pulled out). Was able to fix the primary between sets, but I would have delayed the start of the show if I hadn't had the backup.
Luckily, I run FOH so I don't need double amps, but I do have a backup of everything I need to gig (cables, DI, mic, strings, batteries, etc). Not everything is equal in quality to my primary gear, but the show could continue.