I keep mine in mason jars in the freezer. Bud stored at room temperature gets noticeably weaker after a year, even in stored in vacuum sealed bags. I've kept little samples of buds in the freezer for over 10 years without much loss of potency.
After 4 or 5 years at room temperature, almost all the THC in the bud has broken down into CBN and other less active cannabinoids. After enough time it just gives you a fuzzy body feeling without a high.