This almost goes without saying, but making sure each band member has his instrument on stage is essential to a live show. Depending on the type of band involved, each instrument needs to be accounted for. For example, a typical live rock band instrument checklist would include guitar, bass and drums. The drums are particularly important to check, as several different parts are usually involved. A drummer missing a kick pedal is virtually useless onstage. Band members need to make sure they have backup instruments, such as backup guitars, in case strings break or an instrument malfunctions.
Microphones are essential for every live band equipment checklist. Each vocalist in a band needs a microphone. Even band members who don't sing should have a microphone on stage in order to communicate with the sound engineer and contribute to onstage banter. Microphones are also important in instruments like guitar amplifiers, drums, keyboards and others that don't sound quite as right going direct input into the soundboard. Microphone stands are also needed.
Amplifiers and a public address (PA) system are necessary for a live band show. The audience at even the most intimate acoustic show can be loud, so the band needs to be able to overpower all the noise in the venue. Guitarists, bassists and keyboardists need to have amplifiers hooked up to their instruments in order to carry their sound throughout the room. Patch cables are necessary to plug the instruments into their respective amplifiers. A PA system is necessary to carry vocals and mixes made by the sound engineer.
The smallest piece of equipment and accessories can make or break a live show. Drummers need to make sure they have a good supply of drumsticks, as well as a drum key in order to tune and make adjustments to each of the drums. Guitarists and bassists, unless they play with their hands, need a supply of picks. Extra sets of strings are also a good idea. Guitarists and bassists should also bring tuners, as well as any effects pedals they need to achieve the band's sound.