De-lurking to add my empathy. It drives me completely crazy (short trip!) when my kids make a mess while "helping" me cook. I have 5 kids, ranging in age from nearly 13 (only cooks when forced to) down to twin girls, age 4, who love to help and taste everything.
A couple of years ago, I never let the kids help. It bugged me too much to clean up the mess. My husband told me I was doing them a great disservice, and that they'd never learn to cook if they didn't start when they were interested. I should just let them help, relax and enjoy the process, knowing the most important part was building a good relationship with my kids. Floors can be swept, but kids are only small a short time.
I don't mean to preach - what works for me won't work for everybody else. My house is far from spotless - but then, it always has been that way! :-) I do try to relax and enjoy it more, and that helps keep me somewhat sane.
BTW, that thing all the parent "experts" tell you about letting the kids help cook and they will try more foods? Bolony! My middle child, known online as Miss Fussy Rose, won't try anything new, but absolutely loves to help cook!