On my streetbikes that never see dirt or rain, I clean and lube the chains every 800-1000 miles or so, the chains stay nice and quiet with lube on them during that time. On my dualsport, after one short dry dirt ride the lube is gone...if I want to keep it greasy to the touch, I'd need to lube it continously....which honestly with 4 bikes and a busy schedule I don't really have time for.
So how long do you guys get out of a chain with constant lubing vs less often? If the difference isn't too much I might just lube less and replace chains and sprockets more often as needed