Old Rule:

To not have your account disabled for inactivity, you must log in at least once every 3 months (once a month is preferred). There is no grace period - the disable is instant.

New Rule:

To not have your account disabled for inactivity, you must log in at least once every 3 months (once a month is preferred) or be actively seeding for a majority of the time during your inactivity. There is no grace period - the disable is instant.

Seeding now counts as site activity.