I always upvote my own articles but I never upvote any of my comments. I've been doing this ever since I joined back in July 2016 and I will most likely continue to do this for as long as I'm here.
Well, if I suddenly became a billionaire and got $10,000 for each upvote, I would obviously not upvote any content at all with 100%. But that's not very likely to happen. ;)