General building

The commonest avoidable damage on older property around here is cement. Solid stone and soft brick walls were built to breathe through a lime mortar. Repoint them in a hard sand and cement mix and moisture can no longer leave through the joint, so it leaves through the face of the stone instead. A frost or two later the faces spall off, and what you have lost is the fabric of the wall rather than just the pointing. Hard render over a solid wall does the same thing on a larger scale.

So mortar gets matched to what is already there, lime where lime belongs, and a wall gets raked out and repointed properly rather than skimmed over. On exposed coastal elevations, driving rain and salt bring that decision forward by years compared with the same wall inland.