Bront82 loves this scent, maybe he'll see this thread and comment.
Do you live where it's warm thebeck? I don't remember Bois de Encens having really high longevity, but perhaps the climate might have something to do with it. BdE is more of a fall/winter scent, IMO.
Nonetheless, if you do find the longevity too short, try Avignon by Comme des Garcons. Another wonderful frankincense fragrance that is much cheaper than BdE.