Personally I like to use as big a fender as seems reasonable, 10 x 20 white "Taylor" made which are inflatable, like the boat. Smaller size fenders are easy to stow, but get a heavy wind or precarious docking situation and you are playing with fire. If you like your boat protect it. The pads Bou posted a picture of earlier in this thread work well in most situations, I have some of those as well and they see a lot of use. Always put out fenders, it is a good habit to develop and very cheap insurance.