Self-custody removes counterparty risk and replaces it with operational risk. That is a good trade for many people, but only if the operational side is actually handled.
Start with recovery. If the device died tonight, could you restore the wallet tomorrow from your backup alone? If you have not tested it, you do not know.
Then think about access. A recovery phrase photographed on a phone is a recovery phrase in a cloud backup. Anyone who reaches that account reaches the funds.
Finally, plan for inheritance. Keys that only exist in one head are keys that vanish with it.
