One thing not in the guide is steam condensation. You'll see small puffs of steam coming from the bottom. If enough deposits form around the aluminum tube connected to the rubber hoses, or the hose is old and brittle, it won't seal well so steam leaks out were the metal meets the rubber tube held by the spring clip, this condenses on the bottom as drips and drabs, rather than a bigger leak caused by a hole in the hose. Doing the vinegar clean on coffee maker while it is new will reduce the build up and prolong the life but it will happen anyway just at a later date or when the hoses give way. So if you intend to look for leaks, have a spare hose ready as even if it isn't leaking, just removing it could tear a worn, old, but still good hose.