Hotel card keys may seem convenient, but they can be troublesome. Often, removing the card key turns off all room power, making it impossible to charge electronic devices while out. To resolve this, insert a different card, like a point card, instead of the key when leaving. Some hotels require a long key to be inserted for power. In such cases, I recommend inserting a toothbrush when going out. Be aware that in some hotels, the refrigerator power is off at check-in for energy saving. Ensure it's on, or your drinks won't cool. Japanese business hotels are functional and convenient, but knowing these tips about card keys and refrigerators can make your travel even smoother!