A masonry wall is a system with a deliberate weak point. The joint is softer than the units so it absorbs the movement and lets moisture out, which means mortar has a service life and brick largely does not. Maintain the joints and a wall lasts a century. Leave them and water gets in behind the face, freezes, and starts taking the units apart – and the single most common cause of badly spalled brick we are called to is a previous repair done in mortar harder than the brick around it. Matching the material is not a finishing detail here. It is the work.