Is it safe to store valuables in hostel lockers? What size padlock do I need?

Most hostels in Portugal use lockers that fit a standard 40-50mm padlock. Bring your own — a lot of places charge €2-3 to rent one and they're usually rubbish quality. I use a TSA-approved combination lock so no key to lose. The lockers are generally fine for a laptop, camera, passport. I've done 60+ hostel nights and never had anything stolen from a locked locker.

Get a small retractable cable lock too — useful for zipping through your bag handles if the locker isn't big enough for everything. Some hostels also have a reception safe for passports which I prefer for documents.