I rarely buy butter because, at least around here, they don't sell it by the stick and I can't get through a whole 4-pack before it goes bad. I've tried freezing it, but even that doesn't keep it fresh long enough. I usually have a margarine/butter spread in case I happen to have bread in the house, although that rarely happens.
Any recipe that calls for butter usually gets olive oil, at least if it's a saute situation. I don't bake much at all, so I really don't have recipes that REQUIRE butter.