Please keep in mind that accounts and IRC nicknames are two different entities, while it is possible to register IRC nicknames to your DareNET account.
That said, we do not expire accounts. IRC nicknames are considered expired after 60 days without use (this is done automatically). Nicknames which are at least two weeks old, and which were last used less than two hours after their creation may also be considered expired. These limits do not apply to staff-reserved nicknames. Also, if the nickname you want to register is the same as someone's account name, we may be reluctant to drop it, even if it's expired.