Unpaid jobs

I don't do paid work, so if anyone asks me to come take a photo of them for whatever reason, it's always for free. However I do sometimes worry that I shouldn't do it. There are so many struggling professionals around (including some friends of mine) that I'm taking business away from them.

I also wonder whether people (customers) are happier if they pay for the work, maybe they value the results higher than when they're free.

Makes me think anyway.