The SAMi camera stores the most recent 1,000 recordings and can save as much as 138 hours.
SAMi recordings use about 4 Mbytes per minute. 1GB can store a little over four hours of video. Note that iOS devices overstate their storage, a 16GB iPod actually has about 12.6GB of storage available for use. The rest is consumed by the operating system and formatting.
The 16GB iPod stores up to 50 hours of recordings.
The 32GB iPod stores up to 122 hours of recordings.
The 128GB iPad stores up to 512 hours of recordings.
If you only enable recording at night (recommended) you should get from 1/2 hr to 3 hrs of recordings each day depending on the level of activity. So the 50 hours of record time on an 16GB iPod should store at least two weeks of activity.