It depends on what you are going to use it for.I have a 6o psi 1.4 gpm and I have a 50 foot hose and it works great.I use it for sealing so I didn't want to many gpm's.I also use it to apply stripper.If you are using it to apply cleaner 3 gpm 100psi would probably work with 100 feet of hose.I have mine attached to a cart with a deep cycle battery.It takes 15 minutes to charge and runs all day(I mean ALL DAY!) I use a bunch of attachments I made with quick connects.The hose I use is a small 3/8 garden hose on an enclosed reel,I bought at lowes ,it is perfect .