A skimmer can make the difference between enjoying a pond and beginning to resent it. A properly functioning skimmer will collect the leaves and anything else that lands on the surface of your pond into a net or basket, where it can be easily disposed of. Without a skimmer, you are sentenced to a life of constantly cleaning leaves and debris from your pond.
They are a real bargain when you consider the minimal expense they add to your pond. Note: Even if you plan to build your pond inside your house, where there would be no leaves, you should still install a skimmer because in addition to leaves, they skim off the dissolved organic compounds (DOC). Dissolved organic compounds will form in any pond and if not removed will causes an unsightly film and bubbles on the surface of the pond. A skimmer removes this film by constantly skimming off the top surface of the pond.