re: If you're planning on flying to Canada - read this

You need to get our more. Canada and the US have had this agreement for some time. It is far better to get through the customs check there before boarding than it is to do it here in the first city you fly into the US when you have to hurry to catch a connecting flight on to your final destination. Believe me it's far better.

The 2 hour guidance is very much standard everywhere now for international flights. If you travel much you'll learn its much easier and enjoyable to do that than it is to be running like crazy folks trying to get through checkin and security and on to your gate. Much better to start a trip relaxed and not in a panic.