New flooring often changes the relationship between the floor, baseboard, shoe moulding, and door casing. Small gaps may be solved with shoe moulding, but larger or uneven gaps usually need a more careful trim plan.
The cleanest approach depends on the existing profile. Some rooms need baseboard reset lower to the new floor. Others need shoe moulding added, inside corners coped, and outside corners mitered so the repair looks intentional.
Caulk can finish a tight paint line, but it should not be used as a structural filler for wide gaps. Oversized caulk joints shrink, collect dust, and make the trim look like a patch instead of finish carpentry.
Door casing is also affected by flooring changes. If casing was undercut or left short, small plinth blocks or casing replacement may create a cleaner transition than trying to fill the missing piece.
A trim repair is successful when the base line looks consistent around the room and the painter has a clean surface to finish.