Spouts generally are fairly easy to replace. They usually fall into two types...push on, or screw on. The push on types have a set screw accessable from underneath that needs to be loosened first, then it just slides off (unless yo uneed to cut the caulk). The other type is screwed on, so you just unscrew it. Replacing it requires some pipe dope or teflon tape. Sometimes a handle from a screwdriver into the downspout gives you the leverage you need to remove it. A wrench could be used to remove it, but not a great idea (unles syou have a strap wrench) to install the new one.