Ever wonder why static systems often start to leak after a couple of years? See the little plastic insert between the two tubes in the photo? It is supposed to be inserted into the end of the tube. Without it, the tubing will eventually start to collapse as seen on the right tube and cause a leak!
Problem I had with the static lines installed for the altitude hold sensor for the sTek autopilot: apparently the tubes were not ‘approved’ and they got brittle and shattered in the tail area. Took about 15 years from installation, and were not caught during the annual inspection.