Our reed diffusers will last approximately 12-16 weeks. A key factor of the exceptional life of our diffusers is that we don't use any alcohol in our base - this results in exceptionally long life and amazing scent throw. Initially, the liquid in the bottle will go down quicker, as the dry reeds absorb the liquid. The rate of consumption will then slow down. By turning the reeds regularly, for increased scent throw, the consumption will speed up. Environmental factors such as direct sunlight, heat and dry conditions will also affect how long the diffuser will last.