This is exactly what I started doing a few years ago, and it's worked wonders. I do still occasionally forget things, but I notice their absence much sooner, an

This is exactly what I started doing a few years ago, and it's worked wonders. I do still occasionally forget things, but I notice their absence much sooner, and not when on a flight halfway around the world (it's happened.) I have the exact same configuration too. Keys, phone, wallet. Everything else can easily be replaced at an opportune moment given I have those three items. When traveling, I replace the keys with my passport. I still bring keys usually, but I put them in my carry-on so as to avoid dropping them. Keys are easily replaced anyway, given a phone, wallet, and passport, so it doesn't matter so much if they go missing then. The passport however, I keep close at all times, it's the key to replacing everything else. The other items, phone, wallet, just makes it easier. This habit has saved my skin more than once.