I see truth and perspective as much of the same thing. Just because something is true to us today doesn't mean that will always be the case. "Our truth" is a way to recognize that we all have a different perspective and truth and that none of us have the "whole truth" as that would require us to be "God" or the collective consciousness of all things. The only truth that we can ever know is the truth we know when we know it and like you say, change is constant, so our truth is not constant as it expands just like our perspective and consciousness. This is why I try not to get too fixated on my own beliefs as I know that over time I will question them and change them. I find that "religious people" or anyone that firmly holds on to ideas that were taught or learned via external input often feel personally attacked by questions that make them reconsider their own beliefs, but part of consciousness and self awareness leads to questioning and breaking down our own beliefs in search of our ultimate truth (at least from my perspective...) and the more willing we are to let go of "learned" or "taught" beliefs and discover what we personally believe based on our own experiences, the easier time we have with change.