If I come back six months after leaving, do I start from zero?

Most of the time, no: after cancellation, the account stays accessible read-only for 30 days and final deletion only happens after that window — returning within it finds your settings intact. Beyond that, if deletion has run, the conversations are gone: script, thresholds and settings rebuild in a thirty-minute session, starting from your export if you kept one. The AI's memory depends on what was purged — previously known numbers get relearned from the first exchange. Doing a fresh 15-minute test line to check the current still flows remains the honest method; count a few hours to be operational, not 48 like the first time.