I totally agree with NinjaKlaus. I personally don't even take a phone if I go overseas. I agree that a basic no-contract, no-frills pay-as-you-go phone in the host country is often the best anyway. I also bring with me a very basic digital camera that has no internet capability, so that I can take pics on that.

The issue for me is partly one of privacy, but also I don't want the identity-theft risks that could come with losing my regular phone, especially as it would be more stressful if it happened while I was overseas with it. Furthermore, cost can be an issue - often, bringing your own phone with you will run you up much more charges if you use data or if you make any calls, than it would for the equivalent activity on a pay-as-you-go no-frills phone from the host country. Plus, if you run into issues with your usual phone not working well while overseas, you can't get help with that. As opposed to getting a no-frills phone from the host country, you can at least have an easier time getting help from the local cell carrier store.