Most adults have unopened mail, untouched statements, ignored notifications, and 'I'll get to it' financial admin accumulating. One day annually clearing the 'drawer of doom' prevents larger problems.
What to do on the day
Open all unopened mail. Check all statements (look for errors, unauthorised charges). Cancel unused subscriptions. File or shred. Update beneficiaries. Run net worth calculation.
Most users find errors worth £50-500 in correcting, plus £20-100/month of subscription bloat. One day pays back significantly.