2003 T-100 29,000 miles. Have always used a chain oiler, yes it is a mess but the only component that seems to have wear is the after market 19 tooth front sprocket. Many years ago when I was riding T-120's and Norton's the judge of chain life was one of two things.
Conditions that call for replacement
1. Is there a kink in the chain
2. Can you lift the chain off of the rear sprocket more than 1/4 of an inch.
At 29,000 miles the chain is still snug on the rear sprocket. The (non Triumph) front sprocket shows signs of wear and needs replaced. The rear (Triumph) sprocket looks new. The chain has needed adjusted 4 or 5 times in it's life and then only a very slight amount.
Question : If the chain does not meet the 2 conditions above then it is still in good condition?