From conception to completion.... Usually about 3 to 4 years for the average queen size quilt, longer if I am handquilting it. I tend to gravitate towards more complex patterns and quite honestly I relish the process. I may spend over a year deciding on fabrics or vice versa have the fabrics and spend years deciding on the pattern. Once in the que, the project could easily languish for another year or more if something comes up that takes precidence. Once I start cutting and sewing I can often complete the top in a few months but then get to the last few borders and put it aside for a while and start something new.
I always have several projects going at once in varying levels of completion, I work full time and I quilt for others on my longarm.