Docspedia

Unparked accounts are disabled when 50 days have elapsed since the last recorded activity. To prevent disabling user's accounts we send an e-mail after 40 days of inactivity.
Parked accounts are disabled when 100 days have elapsed since the last recorded activity. To prevent disabling user's accounts we send an e-mail after 90 days of inactivity. Disabling this type of accounts is performed twice a day. Also note that we regularly clean out accounts with very low share ratios.
Peasant accounts are disabled after 28 days.
Accounts with 0 upload/download are disabled after 28 days.

HDTs

HD-Torrents.org no longer supports parking accounts, and in exchange the inactivity grace period is 50 days. If you do not log in for 50 days, your account will be disabled for inactivity. If you are VIP you won't be disabled until the VIP period is over.

BithQ

Accounts inactive for more than 42 days are automatically deleted(unless they are parked; then they get deleted after 120 days)

Greek-Team

Accounts inactive for more than 45 days are automatically deleted, so keep trying.
Unparked accounts are pruned when 28 days have elapsed since the last recorded activity. Parked accounts are pruned when 56 days have elapsed since the last recorded activity. Also note that we regularly clean out accounts with very low share ratios.
Peasant accounts are pruned after 4 weeks
Accounts with nothing uploaded/ downloaded are pruned after 4 weeks