I have a HAWG which is the biggest one I think and take it out every ride. I leave pump shock pump (once randomly lost all air in forks and not been out without one since) tubes and tools in there, which is my minimum for a ride, then for a quick blast i just pick it up and go, or depending on the ride add bladder, food, jacket, spare kit etc.
Amazingly it does actually work without filling it up, i’d rather have too much space and not allways use it all than not have enough and break the zips trying to fit everything in…
Plus if I only have 40 minutes to get ready get out and get back I don’t want to spend 20 figuring out which pack bottle or jersey to take.
Cost me £50 in the crc sale