8 Checklist Items for Performing Guitarists
You never know when and where you could break strings and so it is essential to have a backup set in place for those emergency situations. Make sure you get the same gauge that you are using currently, to avoid any changes in string tension.
If you end up breaking a string, a string winder helps you save those precious minutes on stage, in a jamroom or in the studio. You should try to get one with the string cutter as well. This way you don't have to worry about that pointy string snapping out and hurting somebody.
A tuner device that is portable is an important tool to have so that you can regularly check your tuning from time to time. Many guitarists check their tuning from pedals and processor units and that seems to be the more preferred option in order to gain accuracy of pitch.
Carry a few of these just in case you lose or misplace a plectrum. It always comes in handy to have spares lying around in your gigbag/wallet, in case you end up needing one.
Carry a spare set of cables in addition to what you already use. Many guitarists take this for granted and end up having noisy cables. Having a working backup set with you could very well help your cause as cables tend to have short life spans if not maintained well.
Ensure you have a decent strap that supports the weight of your instrument. You don't want your guitar falling off in the middle of your performance.
Carry a foldable, portable stand that fits in your gigbag so that you don't have to worry about your guitar lying around in a risky place while you are not playing.
If your guitar uses batteries, make sure to carry an extra set with you, in case something goes wrong. You will not always understand the life span of your battery and having a backup is the best option.