I like to think of it as quilting in a series. I use the same pattern for all the baby quilts I make. I even have a set of fabrics I use for the blocks and just get a different background for each quilt. So they're the same but different. Then I do a series of quilts for the girls after they move to a twin size bed. They're square in a square with black sashing. I can use up a mulitude of scraps for those so they tend to look similar. I've made 6 of them so far and I have #7 & 8 started. The boys have gotten either string quilts or a D9P. There are a lot more girls in the family!
Other than those two series my quilts don't look alike. I tend to use a wide color palatte though. I don't care for the Thimbleberries, Kansas Troubles type colors at all and I have noticed the people that favor those colors tend to only use that type of color range.