Had tune up of furnace. Tech explained everything was working well. I did mention that 2 years ago when I had this same service done they put a "watch" on a part that was working ok, but was 14 years old. Tech explained that part was still working ok but was now 16 years old. I asked the pros can cons of replacing now. He explained my options and I did choose to replace it now to be proactive. Work was completed in a timely fashion.