At my club because its mostly hobby the
longbow archers just use one bow for a shoot (might have more bows but just use one for a shoot). But we also have a few more who have heavier bows for shooting 100/80yds then switch to a lighter bow for 60yds and closer. They also have different arrow sets for each bow and for certain ranges that can be changed throughout a shoot.
Changing bows mid shoot isn't an overlly uncommon thing, shooting a heavier bow for the longer distances makes the tradjectory of your arrow flatter and less subject to elemental effects, making hitting the target easier, though you have to be able to pull the heavier weight. When you get to closer you can switch bows keep the aiming mark similar and the arrow still low, but now your not having to try as hard to pull your bow back. Also has the advantage of it doesn't feel as heavy, because you've been hefting a heavy bow. I suppose it also means that your heavy bow lasts a bit longer because its not being used as much. Though saying that you could argue your wearing out two bows so you get a longer wear time, but have to replace them roughly the same time.
Personally atm I only use one bow, I might eventually semi-retire my current bow to closer distances, but for the moment it does the job.