As a drummer, that works a lot you should always prepare yourself for something breaking on the gig — have the replacement gear and parts needed to fix the problem quickly with you so you can keep the gig going. This goes for all the musicians in the band, but from a drummer’s standpoint there are some things that you should always keep around.
Of course, you should obviously always have extra drumsticks. But there are other drum parts that are a must to have around, such as felts, cymbal washers, and extra snare string. Zildjian makes a handy kit called the Drummer’s Survival Kit that comes with all of those things and it is inexpensive. DW has a similar kit called the Drummer’s Survival Hardware Kit that expands the offering with spare tension rods, wing nuts, and more. Other things to have on hand are extra snare wires and duct tape or gaffers tape.
You should also always keep an extra snare head and a spare kick drum head with you — you never know when a head may break. Heads sometimes break even when they are nearly new and you don’t want to be the one holding up the show becasue of something that can be easily and quickly fixed.
Try and be prepared for every scenario and the show will always go on!