I was more worried about removing fillers than getting them in. How was it for you?

When considering fillers, the biggest concern is not the procedure itself, but what to do if you change your mind later.

I am thinking carefully because I heard that while you might be satisfied at first, the shape or feel can change over time.

For those of you who have experience with fillers, what did you worry about the most when making your first decision?
Did your thoughts change at all after doing it?