Patching cracks or a full foundation repair
A thin crack that hasn't grown can usually be sealed and watched. One that keeps widening while doors start to bind means part of the house is still moving, and patching it only hides that for a while. When the house needs support, I put the piers in first and close up the damage after, with tuckpointing for cracked mortar joints and chimney repair if the chimney pulled loose. Replacing a foundation outright is a much bigger job that starts with an engineer.

