I am so completely satisfied working with liquid dyestock, that it is hard to imagine dyeing wool any other way. I can fine tune formulas with brutal accuracy, and I am generally able to reproduce a color of the same formula with nary a 'dyelot' difference. Usually there is no way to tell the difference between two pieces, although this is not always the case. As my technique improves, however, I see differences in dyelot happening less and less.
I realize that most dyers are not preoccupied with the accuracy issue that so motivates me. Many are happy to throw some dye and wool in a pot and stand back to see what happens. I'm not sure if it's the frugal person in me, but I never feel that I have the money to throw around when getting results that I was not after. And I'm not the kind of artist to just throw together colors in a project and take what comes. I find the color planning process to be the most enjoyable, and at times the most frustrating, part of any project. I wish I could be more relaxed about it all, but that is just not in my nature. I envy those who do have this more relaxed approach. I envy the serendipity that brings about an unexpected result that is fabulous. I may never experience that, being so structured in how I do things. On the other hand, my customers benefit in getting a good consistent color when they buy something. (That process isn't perfect quite yet, but it will be very soon.)
Another part of this is that, since I have so many colors in inventory, I don't feel the need to 'build a stash' as many do -- simply putting the colors that may not turn out right into the stash pile. Because I already have the most enormous stash imaginable, I am looking for something specific when I dye for myself. So this also drives my need for accuracy. I guess in my situation I can always overdye the mistakes to a nice primitive brown or black and sell it as a penny rug background!