The first thing that would need servicing on a brick and mortar chimney is the concrete cap. The cap, which is normally designed of poured concrete is the first line of defense against costly water damage. The cap is also the first thing on a brick and mortar chimney to fail.
As a chimney ages, this is a good thing to keep and eye on, if you can. This is especially true for a brick chimney in the Minneapolis latitude. Look for and keep any cracking in the concrete sealed up. This can be accomplished with silicone caulking placed in cracking that develops and also around the location where the clay tile flue meets the concrete cap.
Another source of damaging water intrusion into a brick and mortar chimney is an open clay tile flue. We still see a great deal of chimneys with tiles that are left wide open to the elements. This is not smart and is so easily avoidable. A metal flue hood goes a long way to keeping water out and is really a no-brainer for cheap insurance of longevity for a brick and mortar chimney.