Valuables
The hotel will not take responsibility for your valuables so use the hotel safe. Most hotels in most cities in the world have in room safes. You just insert your own pin code or credit card to gain access. Use it!
In the unlikely case that there are no in room safes, the hotel will provide safety deposit boxes which you can use. These will be accessed by the reception desk.
Passports, tickets, credit cards and cash and jewelry and watches are likely to be your valuables. There are a few cities in the world where it is either required or sensible to carry your passport with you at all times. In the major English speaking cities this is not necessary and your passport can be left in your hotel room safe. Laptops, tablets and phones usually fit into the safe also. If you are leaving these items behind in your room, it is best to leave them in the safe.