How long is a necro?

A number of factors go into whether a thread is determined to be a 'necro'. One of the factors include nature of the information being discussed.

For example, class balance discussions are very much dependent on the patch version that's currently running. So, bumping threads from a previous patch would likely be out-of-date. The thread may be locked and in certain situations, the account may receive a forum suspension for violating Forum Guidelines.