ORChick said:
I remember a case when winging it didn't work for me. My mother could bake a very nice pie, and I learned from her how to make a good crust. She always kept a measuring cup in the flour crock to use as a scoop. My crusts were good, but as I got better at cooking I also got sloppy, which is always a danger when winging it. I couldn't think why my pie crusts were not turning out as they should (I didn't make pie all that often; usually just around the holidays) Finally I looked in Mother's old Joy of Cooking and realized that I was just sloppy scooping the flour out -- "Oh, this looks about right", but of course it wasn't. Now I don't need to look at the recipe, but I am more careful about measuring ... and always get compliments on my pie crust.
I measure for pastry, too. The flour and butter, at least.
I just completed some "research" on pie crusts. I was tired of sticky mess and unreliable results. Saw a video of Julia Child rolling out a crust and it was a life-changing type event. It took her less than a minute to do. So easy! So I started making pies and trying to figure it out. For a while,
I tried weighing out everything and that sort-of worked. Still, if you smash the butter into too large or too small bits, the amount of water you need is wrong and I'd end up with a gummy mess or a dry pastry that cracked when I tried to roll it out. But at the time, I didn't know what was going on. All I knew was that results were unreliable and measuring perfectly didn't always help.
Eventually, I found The Art of French Cooking (Julia Child et al) and used that recipe. She wrote that you should start with cold butter in 1/2" pieces. Smash them into the flour between thumb and fingertips (to avoid heating the butter) until it looks right. Then add a little water, mixing with your fingers, until you get a nice dry-ish ball of dough. Smear it on the counter, bit by bit, then refrigerate. Refrigerate. Refrigerate. This, for butter-users, is THE trick. If you don't refrigerate it, it'll be sticky and you'll have to resort to one of the embarrassing waxed-paper or plastic-wrap tricks that you see on TV. The other trick is adding the water until you have the right amount, not measuring.
I made a table of butter

our ratios (by weight) in a bunch of different pastry recipes. I tallied up the results and the average is 76%, or about 3 parts butter/shortening and 4 parts flour. Most recipes use 70-ish % but Julia's recipe calls for 80%, which brought up the average. Turns out it doesn't matter. Doesn't matter if it's exact or shortening or butter. Figure 3:4 is the ratio for a basic pastry and you're good to go.
Recently I tried an english recipe that called for suet pastry. That was awesome. I highly recommend it.