I always take all 3 of my basses to gigs (they all get used at some point in the set). I also have at least one set of spare strings in each basses case, since they're strung with different gauges. Then I have my C.Y.A. box, it's the tote I use to store my patches and power cords (as well as spare speaker cables, xlr mic cables, and spare guitard strings) in, but the top is a flip up/tool box divider dealie that houses: leatherman tool, pocket tuner, allen wrench sets in metric and sae, small flashlight, de-oxit, a small spool of solder and a coldheat battery powered soldering iron, micro-screwdrivers, a passle of 9 volts, gorilla tape, a lighter, a tube of super glue,a pack of razor blades and 2 extra 12ax7 tubes. Overkill? Maybe....but my guitar player also carries a similar C.Y.A. kit, and we've Covered other band's @$$es on more than one occasion when they weren't as prepared as we are.