When it comes to masonry issues, the question of when they should be addressed and if it is urgent is often asked. The answer is: the sooner the better. Failing masonry could be anything from loose flagstones coming off of your cement porch, mortar or joints in between bricks failing and requiring tuckpointing, to cracking and loose parging (a protective cement layer smoothed over your foundation).
The reason you want to address these issues rather rapidly is simple. The issue is either fixed or gets worse. What I mean by that is that all masonry issues are simply water maintenance issues. Cold, frosty winters, salt, and other elements take their toll on a home. If this is allowed to recur over and over again without repair, more and more water tends to make its way into cracks and behind bricks, causing further deterioration. The issue can become so bad that your bricks start to spall (the face of the brick is seen to practically fall off). The only solution to this is to cut out and replace the bricks and repoint the joints. If you own a much older home (100+ years), it will likely be quite difficult to find a good match, so it is always best to get to the problem before this occurs.