Whether you need to return your room keys depends on the hotel's technology, but in 2026, the trend is shifting toward high-fidelity digital keys that reside on your smartphone, which simply expire at check-out. For properties using physical RFID plastic cards, returning them is not strictly mandatory for security (as the code is deactivated upon your departure), but it is highly encouraged for environmental reasons. Many hotels provide "Key Drop" boxes in the lobby to collect and sanitize these cards for reuse, reducing plastic waste. If you are staying at a boutique property or an older hotel that still uses traditional metal keys, returning them is vital; losing a physical metal key can lead to a "re-keying" fee that can cost upwards of $100. For most major chains, your high-fidelity "check-out" is completed via an app or a quick television prompt, and while you can keep the plastic card as a souvenir, dropping it off is the more sustainable choice.