I advocate measuring by weight, but then again I use stock that's more than 4 months old and still get good results. So who am I to critisize those who measure in teaspoons, pinches and whatnot. I use Caffenol-C-M and C-H for the most part (the latter for 400 ISO films and up), and have really never had a mishap. As John says, the latitude this developer gives is enormous, and probably very tolerant of variations to both concentration, temperature and timing. However there those that get it wrong, very wrong. Mostly because they use ingredients not quite what the doctor ordered. Baking soda is not the same as washing soda for instance. But once you get it right, you'll have no end of fun trying out new variations and films. Have fun.