You are asking for a world of pain if you don't get this very affordable and easy to find accessory before traveling to foreign countries. Like most of the wisdom that I have these days I learned it by doing it wrong a few times before it stuck in my mind.
These days it is one of the first things that I pack because I have found myself in bad situations in the past because I forgot it, or foolishly assumed the entire world uses the same electrical plugs.
Some of them seem absurdly huge but trust me when I say that you need to find a way to make space for it. They fit inside of a shoe and that's not too much to ask.
There are cheaper ones that adapt to just a few types of plugs but man oh man, let me tell you, there are a lot of different types of plugs that exist out there and some of them, I can't really relate to how or why they don't phase them out.
The largest plugs are the ones that make the least amount of sense to me such as the ones that are commonly used in parts of Europe and also places like Malaysia.
I can only guess how this came into being in the first place but I would imagine they are more durable than the standard North American plugs. For me it just seems like a powerstrip would just be a messy and heavy disaster but since it has always been that way, it probably has to stay like that.
The adapters I'm talking about will fit this and all the other types of plugs that I have encountered in the dozens of countries that I have visited.
Also, I think it is important to get a "real" brand when buying your adapter. They will cost a few dollars extra but the quality ones also have a built in surge protector and this can be very important in countries that have less-than-awesome electrical reliability. Many countries that I have visited had spotty electricity on a daily basis, and this can reek havoc on sensitive electrical devices. I've had a Kindle that was fried because of it.
The ones that I have faith in are available on Amazon and probably any other online store. I also have seen them in Best Buy, Wal-Mart, and other retail outlets of this nature. You can find them near the power-strips for the most part. You should budget around $30 for one of these to get the full power surge protection and of course, be wary of brand names you have never heard of or - and I mean no offense by this - any of the ones that have poor English spelling and grammar on the packaging. If the company cant manage to do that part of the process correctly, I generally don't have much faith that the product itself is quality.
I have a "travel bag" in my closet with all the things that I consider to be absolutely essential for international travel and this is one of the items that is in that bag. I think it is one of the most important things to remember to bring with you.