Spot tuckpointing or redoing the whole wall
Most walls only need spot tuckpointing, and that's where we start, since the sound joints are worth keeping. A whole-wall repoint makes sense when most of the joints are crumbling, cracked or worn back from the face. Replacing brick is a different job, and it's only worth it where the bricks themselves are broken or their faces are flaking off, because repointing around them won't fix that.
What shapes the cost of tuckpointing
Repointing is mostly hand labor, so the biggest factor is how many joints are failing and how deep the damage goes. Height and access matter, since a second-story wall or a chimney takes more setup than a garden wall. Matching an older mortar's color and strength takes extra care, and lab testing of the original mortar adds cost, though it's usually only called for on historic jobs that must closely match what's there. Fixing a moisture source first adds to the bill too.