Me, DW, DS, DD1, and DD2 each have a sealed envelope from each other with all account numbers, locations, IDs, Passwords, etc. We get together New Years Days and exchange new envelopes with any deltas updated. We started this when my Mom died. She was not wealthy, did not have any debt other than current monthly bills, but she had almost a dozen accounts with between $100 and $3000 in each. It was 3 years before the last one surfaced.