I've been travelling long enough to remember when all you needed were some AA batteries every so often and you were set. Now it's all chargers, chargers, chargers. Make sure you stock up on wall plug adapters before you go, in fact go to A'zon and buy more than you think you'll need because guess what, you're going to be fighting for plug space in your room every night. It's just amazing how devices have taken over. Do some math beforehand and don't get caught short. You might also find things charge more quickly with the juicier juice.
Also, rookie mistake here, keep a charger on you WITH THE RIGHT ADAPTER as you travel during the day and on planes and trains. I failed to remember the part in all caps but luckily didn't get caught out. Best case scenario, you can use a USB port without a charger since that voltage is universal.
The good news is all modern chargers run on either US or 240V electricity, so there is no longer any need to lug those big heavy transformers around. Legal disclaimer - MOST chargers are like this, read the fine print on yours. Every room we stayed in had a hair dryer but my wife has very specific needs and wants, so she purposely bought a 240V unit before we left and was glad she did. It had the two round prongs so still needed plug adapters in some situations but it put out the quantity and temperature she needed for her 'do.