Bricks, Masonry, Asphalt and Concrete - cracks between brick and morter

I was doing a walk around house inspection the other day and noticed there is a few places here and there (not noticible unless your looking for something wrong) where there are small cracks and gaps between bricks and morter. In addition, I noticed 1 foundation block corner brick had a gap between the brick and the morter around the entire brick. I assume this all is caused by settling since the house was built in the late 70's. My concerns are as follows:

Can and should I fill these cracks?

What products do I use?

I noticed a few places where the small crack were noticed by the previous owner, and he squirted some clear caulking in the crack - is that good or bad?

Mortar and brick expand and contract at different rates. Shrinkage
cracking is generally not a problem, provided it is scattered throughout the wall. If you have a zig-zag pattern, or even worse, cracking through the brick, then you have more serious issues. To "repair" shrinkage cracks, make sure your weeps are clear and consider an invisible sealer.

If you have mortar eroded around a corner brick, low down on the wall, you probably have water running down the wall to that spot. Repoint it to repair, and try and gutter water away from the corner.