How entry is done
Non-destructive first, drilling as a last resort
The goal of any lockout is to get you back in without leaving damage behind, and for the large majority of locks that is achievable. Standard residential and commercial cylinders can usually be opened with picks or a bypass tool that works with the lock's own mechanism, leaving the lock fully functional afterward. On a vehicle, a wedge and a long reach tool can operate the interior handle or the electronic unlock without touching the door skin or the glass, on most models.
Some situations do not allow a clean entry. A lock that has already failed internally, a high-security cylinder built specifically to resist bypass, a deadbolt thrown on a door with no accessible gap, or a key snapped off deep in the plug can all mean the cylinder has to be drilled. When that is the case, it is explained before anything is done, along with what it means: the cylinder is destroyed and will need to be replaced or rekeyed, but the lock body and the door are preserved. Drilling is a controlled last step, not a first move, and a locksmith who reaches for a drill before trying anything else is one to be wary of.
After entry, whatever contributed to the lockout gets addressed. If a key broke because it was worn, a fresh key is cut. If keys are lost, rekeying retires them. If the lock itself failed, that becomes a repair or replacement conversation.