Why it works
Subscriptions and small recurring costs creep in silently; a scheduled quarterly nudge is the only thing that reliably catches them. The email even carries its own justification — "if you do this every quarter…" — so future-you doesn't argue with the reminder.
Make it yours
Point it at wherever your spending lives (your accounting tool, your card statement) and add a target, e.g. "cancel at least one thing."