I'm starting to see a pattern. Both this answer about Cassini liquid propellant engine and this answer about ion thrusters discuss a particular necessity for gimbaling engines to keep thrust aligned with the spacecraft center of mass (on average).
While thrusters could be used (in at least some cases) to correct for mis-aligned main engine thrust, it's a waste of propellant compared to simply pointing the engine's thrust in a direction that doesn't produce a torque on the spacecraft to begin with.
Is it pretty much a given that all (or at least practically all) deep-space spacecraft have gimbaled engines? Or have some used vectored thrust, or found other solutions?
edit: to clarify, I'm asking about actual existing deep-space spacecraft, not hypotheticals or future plans or ideas. If it's still on the ground but almost finished and funded for launch, that's close enough to being an existing spacecraft for this question.