That depends of course – how many line ups you have? Maybe you're the type of band who can go out as a duo at the smallest size and an eight piece as full band!
So you may have just one which is probably the most common, but then it's also quite possible you'll have 2 or 3 (or even more).
Just remember, however many you need to create, always add as much detail as you can. Make your sound engineers life easy!