Extended cooking sessions, more common during festival or gathering periods, also mean the chimney's exhaust motor runs for longer cumulative hours within a shorter calendar span, which can be a reasonable time to schedule a motor and ducting check if one has not been done recently, given the additional operating hours accumulated quickly during such periods. Charcoal or carbon filters, present in ductless chimney models that recirculate filtered air back into the kitchen rather than venting outside, saturate with odor-absorbing capacity based on cumulative cooking volume rather than calendar time, meaning a period of unusually heavy cooking can exhaust these filters considerably faster than the manufacturer's general estimate assumes.