Popular, as with most hard woods, unlike evergreens, have a tendency to dry rot if exposed to weather, which is why it's not used in building construction. That said the boxes should still last for5-6 years before developing any serious problems, if painted. The various varities of Fir, Pine, and Cedar (including Cypress) will last for decades if properly cared for. If you like wood working rebuilding your boxes every few years shouldn't be a big problem.