I have been creating custom brushes for over 15 years. I started by giving away a lot of my brush packs and then over time I began to offer a few paid sets. It has since then become a bit of a profession for me. I won’t be retiring any time soon from it but it definitely helps cover costs and it appears to be something that my fellow artists enjoy. So I continue to make them. One of the neat things about this process is as I create a new set I use the feedback from artists that use them to make them better. So of my best brush ideas were from suggestions from current users. I think in the end it helps us all out which is always a sign of a good relationship.