I draw an encounter whenever there's travel. If the one that comes up fits the locale, and seems like it will make for an interesting roadbump or feed into the campaign in some way, then I'll keep it. Otherwise I ignore it and we move on. If there hasn't been an actual encounter in a little while I usually pluck something from the mood elements (which can sometimes eat up a surprising amount of time, or lead to some surreal happenings).
That said, after just a few sessions I realized I didn't love most of the encounters in the book. So I've homebrewed a few, or just tweaked the ones in the book, but I've also found this generator dedicated to older editions
, and it has some really fantastic material.