I'm curious about how native speakers actually respond to the simple question of 「お元気ですか。」 I'm currently going into my third year of studying Japanese. My first-year Japanese professor impressed upon us that no matter what, always respond with 「ええ、おかげさまで。」 That always seemed very formal to me. In fact, my second-year professor often responded with just 「はい、元気」 and a Japanese friend of mine seemed surprised when I used 「おかげさまで」 to answer him.
I've done a fair bit of searching around on the internet, and I've seen mixed responses, so I'm assuming it's a very situational type of thing. When would you use 「元気です」 vs 「おかげさまで」 vs some other response?