Very often our clients will ask us at what point they need to address their masonry issues or brickwork. The answer is simple: any time you see a deterioration in the mortar joints between the brick (if the joints have been washed away and are very recessed, the joints are broken and falling or there is a separation between the joint and the brick or stone) you should have this repaired. When the joints are seen to fail there is always the potentiality of water coming in and the failure of masonry is simply that- water or weather issues.
If bricks or deteriorating joints are left to accumulate water, the deterioration will continue to grow and water will sit. Your repair could go from a one day job to much longer simply because a small repair needed, was left undone.