Fantastic link here: http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv352.shtml It's very well explained :) However, to summarize: We use "ever" to mean "at any time", for emphasis (i.e If I ever catch you, I'll...) and occasionally to mean "always" (i.e As ever, they couldn't agree VS as always, they couldn't agree). We use "always" to mean very often or on every occasion.

They are not directly interchangeable. Here are some examples. I always do it Would you ever do it? If you ever do that I will not be happy You always do that