My mother loved lavender and kept little sachets of it in all her dresser drawers to keep her clothing smelling fresh - she also used it when storing out of season clothes because it works well as a moth preventative. It's a frequent ingredient in potpourri and its scent is known for its ability to aid relaxation. A quick search for the benefits of lavender oil will turn up all sorts of interesting healthy properties, but none of those are what inspired me to plant a small lavender plant in my yard - I just like the way it releases its scent every time I brush by it going down the driveway. The fact that bees and butterflies also like it doesn't hurt either!
My plant, a French Lavender, is now about 6 years old and I trim it back pretty heavily every year, but it still continues to get bigger every time. Once it has passed the height of its bloom season, I trim off the flowering spikes carefully and hang them in a dry spot within a large brown paper sack. Weeks later, when the stalks have dried out completely, the flowers are gently stripped form the stalks, though in many cases, they will have already fallen off on their own.I then put it into little sachet bags and hang them in the closets and pop them into drawers.
Pure lavender essential oil is quite expensive, but it's relatively simple to make an infused oil with lavender by covering the blossoms in a high quality oil such as extra virgin olive or almond and letting the mixture steep in a warm spot for several weeks, giving it a shake daily to keep the blossoms covered by the oil. It's important that the blossoms remain below the surface of the oil so that they stay out of the air to prevent mold from developing. Once the mixture has steeped well, strain the oil off through cheesecloth and store in a dark jar. It makes a very relaxing massage oil and will keep well for at least six months.
From the pictures, you can see how lavender goes from a bushy green mound to a purple pincushion in a matter of weeks in the spring.