You will have a 30-day trial to see if you're interested in the subscription, which I have found worth it. There are two options - 10-day and 30-day video history. I chose the 10-day.
If you do not have a subscription after the trial ends, no video is available on the servers for your review. With a subscription, you can download your videos and do whatever you want with them as well.
As for the recording timeline - I have found that the Nest Cameras will record for as short as 5 seconds or for sustained periods, as long as motion or associated sound continues. These times can be longer if you choose to setup 'priority boxes' in your camera's field of view.
Hope this helps. Enjoy the camera.