I recently noticed some mostly-vertical cracks present on some exterior walls.
In case it is relevant, this is a South Florida home built in the mid 50s. The downstairs walls are CBS (Concrete Block Structure) and the upstairs bedroom/bathroom walls are wood frame.
EDIT: Added images. Sorry for the quality (camera phone).
East wall (front): Crack that starts about 3 feet from the ground and is about 6 feet long. The crack itself is about 1mm wide. I am not sure how deep is is. There are some spots where there's a little bit of the wall chipping off, but the chips are not deep and are maybe 2mm wide on either side of the main crack.
This part of the house was added on a while before we bought it as an expansion. The crack seems to have surfaced in close proximity to where the old wall would have ended.
East wall (rear): Crack starting in the corner of a window and working its way down about 3 feet. Same thickness as east wall (front) crack. Nothing chipping off yet.
Rear wall: Crack same as East wall (front) description.
West wall: Tiny cracks... thinner than the others I mentioned and not even a foot long, but there are 3-4 of them joining together.
Upstairs: Larger crack (between 1mm-2mm) starting at the corner of one window, going down about 3 feet and halfway across to the other window corner. The other window corner has its own crack starting there which works its way down about 3 feet as well, but doesn't join with the other crack.
My neighbor tells me that a few months before we bought the house, the upstairs window was actually a sliding glass door (yes, a sliding glass door to nowhere) and was replaced with a regular window. This crack has me most concerned.
Those are the major cracks I've noticed. I'm hoping to find out two things:
How serious is this? I mean, really, is my house falling apart?
Is this something for which I can perform a quality repair job (if so, how) or should I seek a professional?