+1 for the pulleys, if these are pointed, the need to be replaced, if you have done 2 years of commuting on it, could expect to have to replace the whole drive train (cassette, chain, pulleys, cables & possibly chainrings after that long, if in daily use, dependant on conditions traveled in, periodic maintenance carried out and distance traveled.
derailler hanger, Bottom Bracket & freewheel/cassette hub should be checked as well