Hi - interesting topic! I have a lot of spare gear (small items) with me, but I don't carry a backup keyboard to gigs. I have not had a keyboard fail in ~40+ years of gigging, thankfully. (I'm 60 now) I was thinking about how ~50% or more of the places I play, have a piano in the same room (often a well-maintained grand piano), so that would be my first 'backup plan'. It would not be as dynamic and varied as what I do on my arranger keyboard, but I could do an hour or so that way no problem.

I was also thinking about how ~50% of my gigs are instrumental only; no vocals at all. The places have had me coming back regularly for 20+ years now, and many of them want me to come weekly or monthly (I don't do the weeklies, but I have a bunch I do once a month) ... I feel I give them plenty of variety, dynamic-ness (?word?) and changing sounds/styles/types of music, etc. etc, that they seem to overall enjoy the instrumental. Some are "background music" like a dinner or cocktail party, but most are "concert style" where they set up say 100 chairs all facing where I'm playing. I interact between songs (I'm a quiet-natured guy, so I don't tell jokes and stories much, unless they 'flow' from other stuff I am talking about - about the songs/music, taking requests, answering questions about me or my rig, etc. etc.)

The venues are 55+ communities (I'm doing more and more of those), plus retirement communities and "active adult" neighborhoods, and a few "non-senior" places also.

I have a duo version of what I do; adding a man who plays guitar and sings (and for those, I do some occasional harmony vocals) ... so for gigs where they really want a vocalist, we do it that way. (I'm just not a "solo vocalist" kind of guy! :-)

Anyway, interesting topic . . .

Jim