There's no choice for just "Yes". I don't have matching or complementary pairs though.
I've been bringing a backup for years. The last gig I didn't bring one was last summer. For whatever reason, I just brought one instrument. Literally the first time in years I've only brought one bass to a gig. Of course, disaster struck. I got to the gig in time to setup and sound check to find that a last minute opening act was added. I had time to set up my rig and run my cables. Five minutes before we start, I do a line check and my bass fails. Took a few minutes to figure out it was the bass. If I had a backup it would have been no problem. Instead, I'm making frantic phone calls looking like a total amateur with a large audience waiting for the band to start. I ended up playing the first half of the set with the guitar player's backup guitar through my octave pedal. Ugh.
Never, ever again.
I don't do this for a living, but I take it seriously and I do get paid for it, sometimes quite well. I consider myself a professional and that means being prepared. That means a backup instrument.