I know it's recommended to change chains and cassettes regularly but what about chainrings? I've covered around 9000 to 10000 miles in the past 2 1/2 years on my Boardman Road bike and am currently on the 3rd chain & cassette (latest change was earlier this year) but am still running the original chainrings and it's starting to feel quite rough. The teeth look quite sharp and pointy compared to the flatter tops on the rings on my other bikes (much lower mileages and less hard ridden) so I guess they have worn but should they be replaced a.s.a.p. or can it wait for a while and then replace them at the same time as the chain & cassette at the end of next winter? Also is it better to change the whole chainset including BB (which seems to be running smoothly) or could I get away with just changing the rings themselves?