Is it really necessary to overhaul the entire drivetrain every 5,000 miles, or is this just an outdated industry standard perpetuated by manufacturers looking to sell more parts? Ive seen some proponents of the clean and lube method claim that a thorough cleaning and lubrication of the chain and derailleurs can extend the life of the drivetrain by thousands of miles, but Ive yet to see any concrete data to support this. Whats the real story here? Are there any reliable studies or tests that have been done to determine the actual lifespan of a drivetrain under various conditions? And what about the effects of different lubricants and cleaning methods on drivetrain longevity? Can we get some hard numbers and empirical evidence to back up these claims, rather than just relying on anecdotal evidence and hearsay?