How long can Photo Booth record video?
Your HD storage space is the limiting factor

There is no reasonable limit to the file size of Photo Booth video's. Photo Booth stores video's with AAC audio and H.264 video compression.

Video will take the most storage space. The H.264 uses a lossy video compression method. The amount of compression is usually defined by the amount of motion in your video. A tripod mounted camera recording of a vase with flowers will result in a smaller file size than a hand filmed recording of a flock of birds.

So your answer in short, your HD storage space is the limiting factor. Record for one hour and see how much space you needed for your type of video.



If you are only interested in 'changes in your scene', try another option, like senstic (the first google hit, nothing special)