It is always good to have a few citrus trees in your backyard. The juice and zest from orange, lemon and limes is very usefull in cooking as while as in making a varity of drinks. I have a meyer lemon and a kaffir lime tree in my back yard, its great to be able to go outside and grab citrus when you need it. The kaffir lime is not very common here in California, but it grows well because of the warm weather. Its use is mainly the leafs of the tree. The leaves are very fragrant and used in Southeast Asian cuisine. If you ever had a Thai coconut curry then you will have tasted it, it is a addicting flavor and I'm glad I have a tree close by. Look for the leaves in the frozen section of good Asian markets.