Does vision change? - In my 30+ years in the medium I have come to the conclusion that vision rarely changes but that it can evolve if you are working and paying honest attention to the work. By honest attention I mean if you are making images (as has been mentioned) that are basicly repeats of work you have seen, then honestly admit that to yourself, pat yourself on the back for having accomplished it and then move on. Rather than repeating it again and again. Breaking free of this can sometimes be as easy as changing general subject types. (landscape to documentary - as has been mentioned) Or changing equipment (8x10 to Holga or vis versa) Or it might be to stop treating your subject matter as being "sacred" - meaning - thinking that one type of photography is more relevant than another.
I believe that each of us learns the medium a bit at a time. Be it; composition, light, technique, etc., etc., etc. and we might consciously spend some time on each. The order in which we work on these are different for everyone. In the end what we are attempting to do is learn how to speak through this medium and the more we learn, the more clearly we are able to speak and have our message heard. We are slowly building (in a real way) a visual vocabulary. First we learn the A B C's, then how to put together full words, then to construct sentences, until we finally are able to tell complete stories with our images. At least I know this is how I have come about making the images I do today. But of course this is in retrospect.