When you're in Europe, watch out your wallets. Some can read your credit card info remotely. Cover it with aluminum foil - patent pending. :). I prefer to pay in local currency as much as possible.
When you're in S. America, your hotel safe may not be safe. Kidnapping is a past time in many S.American countries.
Indians survive by less than $2 per day. When you're in India, everybody
tries to cheat you; I do not blame them as $10 is a lot of money to
Take a picture of your credit card including the back for the phone number and your passport.
I would stay away for crime areas and trips that demand more than my body can handle.