I don't ride in any particular bad area but after every two rides I clean my chain with a chain scrubber and my cassette as well as my chain rings and rear derailleur cogs to be free as much from road debris as possible. Am I OCD???? Why sure I am! But my chains and cassettes last............plus I get mental reprieve by getting alone drinking a nice cold Stella or Sam Adams while partaking in a fine stogie and clean my bike! Therapeutic you might say!