“How Long Does One Puff of Weed Stay in Your System?”… This topic can be difficult to answer since it is dependent on elements such as the size of the hit and what constitutes a “one hit.” If you take a large bong pull then cough, it might linger in your system for 5-7 days. A moderate dose from a joint can last 3-5 days, whereas a few hits from a vaporizer may last 1-3 days.