Jester David
Hero
With bards, druids, warlocks, and the like a party with both is likely on the minority. A large minority maybe, but still a minority. There's a lot of combinations of party composition.I'm guessing "cleric and wizard in the party" is probably more than half the parties out there.
And even in parties with one or both, not every cleric will prep bless and not every wiz/sorc will learn haste. There's a lot of offensive PCs of both that are not focused on buffing, or support clerics that focus on healing.
So of that minority with a wizard and/or cleric a smaller minority will have bless and/or haste.
And of that fraction that do have one of the spells memorized, it's unlikely to be used every combat, even at high levels.
So it's very much not all the time.