Repairing an old brick wall or building new
If the brick are sound and it's the joints that are crumbling, the wall usually doesn't need replacing, and brick pointing can bring it back by cutting out the worn mortar and packing in fresh. When a wall leans, has cracks running through the brick themselves or keeps soaking up water, I'd rather fix the cause and rebuild than patch something that'll just fail again. At the estimate I'll show you which one I see and why.

