You can buy a paper pass. The disadvantage is that you have to decide at time of purchase which date you want it to start, and you'll pay postage.

If you buy the app version, you can choose a start date later, within 11 months of purchase.

Either way, you have to record the trains you take - either by writing watch train into the paper diary, or Singh it in the app. It's the same idea.

The paper pass does have something going for it - there's no risk of software bugs, and it doesn't ruin out of battery.