Pond Cover
To protect your pond, you will want a pond cover. There are a few different reasons you would need to protect your pond. One is if there are a lot of leaves falling, or you are in the midst of a windy season, you want to keep as much debris out of your pond as possible. This will help save your filter.
Another reason to invest in a pond cover is to protect anything living in the pond. During the winter you need to keep any fish and plants covered. Look into the general guidelines for winter pond care in your area.
If you are going to be away from your pond for awhile, even a couple days, you will probably want to protect it. A pond cover is the best thing for this. This keeps things from getting into the pond, and it keeps any animals from attacking your fish.