The decision: a repair can be fine when the failure is small and the surrounding silicone is clean, bonded, and sound. Full strip-out is usually needed when the bead is loose, mouldy through the material, contaminated, split along the length, or already patched.
When a repair may be enough
A local repair can make sense when one small section has been damaged but the rest of the bead is still bonded properly. That can happen around a minor nick, a short isolated gap, or a finish issue on otherwise fresh work.
When full strip-out is the better call
If the old silicone is no longer bonded, a new layer over the top will not fix the problem underneath. In wet areas, trapped moisture, soap residue, mould, and old silicone residue can stop the new bead from bonding.
Full strip-out means removing failed material, cleaning the bonding faces, letting the joint dry where needed, then applying a suitable wet-area silicone with a clean finish.
Check adhesion before choosing the fix
Brandon would check adhesion first. If the bead lifts easily or has water behind it, patching is usually false economy. He would also check the line of the joint: if the same failure is appearing in multiple places, that usually points to a larger prep or product issue.
What to use
For bathroom, shower, kitchen, and laundry work, the usual product family is a sanitary silicone suited to wet areas and the substrate. Where stone or unusual finishes are involved, product choice needs more care.
The goal is proportionate advice. If a repair is enough, do the repair. If the old bead is failed, remove it properly.