I’m over 15,000 miles and apart from slackening the chain off because it was far too tight off the showroom floor I’ve only adjusted it three times so far, the last time was a little premature when the rear tyre was replaced at around 12,000 miles. Haven’t lost any O rings yet.
I’ve pitting on the chain plates caused by riding on salted roads in winter by but I can’t see it needing replacement anytime soon. It’s only been cleaned once which was to get rid of the factory grease.
EP80/90 gear oil is my preferred choice of lube, a light application applied whilst the chain is hot giving it a chance to wick behind the rollers and spread around the O rings and results in minimal fling next time the bike is ridden.
Correct wheel alignment and running slack is the key to chain longevity. The stock alignment marks are best ignored. The sprocket teeth should run between the inner chain plates, not touch them. Easy visual check is to use a paddock stand to get the rear wheel off the ground and spin the rear wheel backwards several times to settle the chain and then check how the chain is running around the sprocket.