Limits come in two shapes, and they behave differently.
Count Limits — Checked Live
Connected mailboxes, tracked websites, tracked contacts and team seats are checked against your current total. Deleting a contact frees the slot immediately.
Monthly Limits — They Reset
AI emails, AI reply drafts and adaptive recipients are counted per window and reset when it turns over.
The window is your billing period on a paid plan, and the UTC calendar month on Free. On a subscription that renewed on the 12th, your AI email allowance resets on the 12th — not on the 1st.
Retention Is A Ceiling, Not A Consumption

Your plan's retention figure is the longest window you are allowed to configure, not an amount you use up.
Everything above is shown against your current plan in Settings → Usage.