I've done charity knitting off and on throughout the years. I've knit for Dulaan, for The Red Scarf Project, and others I've probably long forgotten about. Like singing in a choir, I enjoy it, but not for the long term. I like a set deadline after which I can move on to other things.
I've learned that I have a fear of getting caught up in some appeal and helping to drown the recipient with unwanted objects. Good research is the key to avoiding that, and communication with the organizers.
I've learned that if you're going to knit for others, the least you can do is abide by their rules, even if that's not how you would do it. Their project, their yarn choices, their patterns. Otherwise, well, see unwanted objects above.
In a perfect world - the same one where I have a supply of baby blankets knit, blocked, and ready for the next addition to my large family - I suppose I would have charity knitting made and on hand for the next appeal. In that world the rules would stay the same, so that whatever I had made would do.