[graeme]

I can vouch for numbers 3 and four. I even had one of two power cables burn out on a month long trip, in a country where I couldn't buy another. Redundancy to the rescue.

Meanwhile, a very small USB drive on my keychain has proved it's worth time and again. There are times and places when Dropbox won't solve your problem.

[circlefavshape]

I just carry a USB cable in my jacket pocket - for charging my phone, and for using the phone as an external disk