If you buy potpourri sachets from the high street or via an online retailer, they will usually last a bit longer, ranging anywhere from 9-12 months. However, the major difference with shop-bought potpourri is that it will always contain chemicals to preserve the contents, so compared to homemade potpourri, it is not such an eco-friendly option. Homemade potpourri can be made using dried flowers, fruits, herbs, spices and essential oils, so you have complete control over what you use and the type of scents that are emitted inside your home.