You have 15 days to evaluate DriverDiary to see if it fits your needs.

When DriverDiary is opened during the trial period, a window will pop up notifying you of how days are left to evaluate the software.

You'll also notice a message in the menu area notifying you of how many days are left to evaluate DriverDiary and a link to purchase a license.

You can register DriverDiary at any time by purchasing a license key and clicking on Help -> Register.