A pellet stove relies on the use of burning wood pellets. How often your pellet stove needs to be refilled will depend on how often you use it! A 40lbs bag of pellets can burn for approximately 24 hours. If you don't burn your pellets continuously, expect them to last longer. Heat settings can also impact how soon your wood pellets burn away. For longer winters or hotter fires, buy your wood pellets in bulk: it's cheaper, and wood pellets can't (and won't) go "off" when stored right.