This very true in my case. Have tied and boxed more flies than I will need on the Bow for 3+ seasons...and don't get me started on chronomids. Thing is needing them has nothing to do with it for me. As Max said love to get new material, experiment and create new things! Tying for me has gone way past functional use... For me it is that I enjoy both the act of tying and the satisfaction of success on a new pattern.
X2, again as I am not buying only what I need, but material I want to try out....at the end of the day I still spend less in a month than some works colleagues spend going out for lunch in a week. All about priorities I guess.