I change the engine oil myself every 10,000 miles as Triumph suggests using whatever oil is on sale and meets Triumph's specs. Certainly not annually that would be way too many miles. Yea I do the final drive probably onece a year.. I have had the valves checked twice and neither time was any valve out of spec. No idea how many tire changes but quite. few. I greased the needle bearings in the rear hub once maybe 10,000 miles ago and they really didn't need it. I am on the third set of plugs and third fuel/air filter did them at 80,000 miles the last time. the plugs looked perfect and all six of them had exactly the same burn. I have done all of the preventative maintenance myself most of the time close to when Triumph recommends. That is the best I can do for you as I am not a very good record keeper and dont get too caught up in doing things exactly according to Hoyle. I feel the motor is as strong as it ever was btw. I am the ride it and have fun type I guess. I am leaning towards keeping the present bike somewhere as a spare and just getting a new one. Heading for the mountains this weekend to get out of the heat and I have every confidence in the old girl, lol.