I found with my stainless steel pipes from Moss that only one connection was held together with a clamp, and the other was just held together by friction. After about a year, the friction connection came loose. So I added my own clamp and now it's fine. Lesson learned: use clamps for all the connections.
Also, much to my chagrin, I found that if something goes wrong with any component on the stainless steel pipes (I accidently dented the muffler), you cannot buy one component for replacement but have to buy the entire system. Solution: I turned the muffler over to hide the dent (from myself).