i guess this is a very personal thing for everyone.. i think a note helps those you leave behind have some form of closure, and it might even help you make sure all of your feelings are out of your system to the best of your ability before you take the final plunge to hell.. it could help build resolve to steel yourself for what you're about to accomplish.. idk, it's a lot of effort, but you have as much time as you need to do it, since you're going to die soon enough anyway; but hey, it's not a school or work assignment, and that's the beauty of killing yourself, it's the only kind of true self-determination some people feel like they've ever truly had, so every part of it is yours to choose based on comfort!