If you want to read a book while out and about, you can download a book onto your smartphone. No need to bring a Kindle. Amazon syncs your devices so when you read ahead at the beach, your Kindle back in the apartment knows where you left off.

Your daypack is not safe for your passport, your credit cards, cash, or any electronic device you don't want to lose. Carry your bag on your side away from the street or subway door. In fact, hold it in front while on the subway.

Barcelona is well-known for its pickpocketing problem. One person who hasn't been a victim doesn't mean nobody else will be.

Do not be fooled by the pacsafe backpack. That is the one I purchased prior to the Barcelona trip. Even with keeping our guard up, our electronics were stolen. These pickpocketers are professional thieves. Btw - we chose the day to lounge on the beach with our kindle and iPad since my husband had terrible blisters on the bottom of his foot. I do not think that an iPhone is a good substitute. Not safeguarding your money and passports in a moneybelt is a risky proposition in Barcelona as well as many other cities.

FWIW, we traveled to London with our PacSafe day backpack. We did not lounge on a beach, where the bag was left without oversight. We mostly walked around and enjoyed the multi-functionality of the backpack. I found it to be just right in terms of size and pockets. It is my favorite go-to day bag now and it doubled as a diaper bag for us.