Sometimes it is only apparent after the fact that it probably isn't a good idea to keep some data. The unforgettable.me app allows you to set a review period (see Days to Review below). Data will not be uploaded until this review period has elapsed, giving you a chance to deleted it before it ever leaves your phone. Under the REVIEW tab, you will see a list of days for which you have data stored on the phone.
Tapping on one of these shows a list of each hour for which data has been collected along with a Delete button.
Tapping the button marks that data for deletion. The data will not be uploaded when marked for deletion. However, you have the option to restore the data before the review period is finished if you choose. If you do not restore the data before the review period elapses it will be permanently deleted. Data is only uploaded when your phone is over 90% charged and has a wifi connection.