How often should I sweep my chimney?

This depends on several factors: what type of appliance (wood stove or open fireplace), the wood you burn (unseasoned wood produces more creosote), your chimney (how strong is the draft), how you burn (very hot, wide open damper or low, mostly closed damper), and how often you burn (every day or only a few times a season). A wood stove burned daily during the cold season, with no secondary burn (not EPA rated) capability, burning unseasoned wood, with a poor drafting chimney and burned as slowly as possible might need to be swept several times a burning season. An open fireplace with a very strong draft, well seasoned wood, burned only a few times a year might not need to be swept more than once every five years.