I prefer to offer to show someone how to do the job themselves. Don't get too many take me up on it, but I have had a few! If it is for a good cause and I am feeling particularly generous, I tell them they can't afford me, but a nice donation to a charity might convince me. I have done some hems and repairs that way. I have even contributed some embroidered articles for charity auctions and door prizes. If anyone asks me for something big like a quilt, I generally laugh out loud and say, "Sure, right after I finish the 10 years of sewing I have for myself." People know I am a very well paid professional in my day job, and I can always use the "I am too expensive" line.
Pam