I rarely make a quilt more than once. Usually, my purpose is to learn a new technique or to use some great fabric I just found. I have made several rag quilts, but only about one a year. Anything more frequents would be extremely boring. You don't say if you are making these quilts for money or for love. If it's for money, then it's your decision based upon whether you want/need the money, but it it's for love and the love is gone, it's time to just say no. The next time you make one to give away and you get requests, offer to teach them how to make it for themselves. I bet you get no takers.