If you've ever bought clothing, you know that it's just not safe to buy something straight off the rack without trying it on. There are many reasons you can't rely on the size label sewn into the clothing, none of which have much to do with the size and shape of your body.The first reason is to do with manufacturers' standards. Every clothing designer and manufacturer uses their own 'block' patterns. These are basic templates for all the basic styles of clothing, and everyone has their own small variations. When I was about 20 I learned pattern-making. I drafted my own measurements onto lightweight cardboard blocks, which were the basic template for all other patterns. I was very careful with my measurements, but my blocks were slightly different to those of the person working on the next bench.Even a 2mm variation in each seam can add up to a significant difference in the overall size of the clothing item. Which is not a problem at all when you're making your own patterns and your own clothing to fit YOUR body, but is a huge issue when you're mass-producing clothing for potentially thousands of people.The second variation comes in with the designer. What is comfortable and or/flattering in the eyes of one designer is restrictive and ugly for another. Or baggy and beautiful, whatever the current trends are. But one designer may like an extra half inch at the waist, another might prefer 3/4 of an inch. Note that's a designer's individual preference, influenced by we know-not-what, and has nothing to do with the size and shape of your body.This difference is called design ease, and varies hugely, even across clothing bought from the same design label or store. I believe that most manufacturers now store blocks in computer systems so designers produce their patterns digitally. Patterns are then printed into card or paper before being cut out ready for placing on fabric.Next the pattern goes to the cutting room. Fabric is layered over on itself many times. Then a skilled tradesperson called a Cutter uses a bnadsaw-like massive cutting knife to cut around the outline of each pattern piece. I'm told that there are millimetres of difference between the cut size of the top piece of clothing and the bottom on.Next stop is the sewing room where more human imperfection creeps in. The machinists blast though vast numbers of clothing items each day. Many are 'piece-workers' which means they are paid by the completed piece. Naturally they want to get through these pieces as fast as possible - wouldn't you? Even if they are salaried, they still are human and with the closest attention, there will be millimetres of variation in their work.At the end, one size 10 and another size 10 will be slightly different, one will be slightly bigger than the other. And here's a really interesting bit: The designer or the factory chooses what label they put onto the garment - it might say size 8, it might say size 10. It might even say size 2.The point is, you won't know how it fits your body until you try it on. I have bought outfits where I've had two size labels difference between the bottom and top, and I'm actually reasonably evenly-proportioned.Now you'd think in this day and age, with all our amazing digital technology, that we'd be able to rely on our clothing being a reasonably accurate fit. All of the manufacturing reasons above is one set of reasons that this can never happen.Your actual basic body template is another. For decades we've believed there are three basic shapes - the apple (round tummy), the pear (heavy butt and thighs), and the hourglass (hips and shoulders in even proportion). But in 2007, TV style gurus Trinny Woodall and Susannah Constantine released a study they'd done which showed there are twelve basic shapes for women: apple, hourglass, skittle, vase, cornet (cone), lollipop, column, bell, goblet, cello, pear, and brick. They also made suggestions about what styles could best compliment each shape.I'm fairly sure that manufacturers don't cater for the three basic shapes - just the hourglass. They surely don't cater for 12 shapes! How can they? It's just not possible to sell affordable clothing when they'd have to produce all the size and color variations they offer, across 12 different body shapes.And of course, 'affordable' is a BIG factor. For clothing to fit even the three basic body shapes, more darts, more buttons, and more detail in general would be needed. That costs time and money, which cuts into the bottom line.Manufacturers have little or no incentive to change? They're selling their clothing anyway. To make mass-produced clothing fit our bodies, we women are torturing ourselves emotionally and physically - why should they change?And why does any of this matter anyway? I know when I go shopping I have, in the past, tended to feel depressed about my body because the lovely dress or top or skirt or trousers look horrible when I actually put them on in the changing room. Many times I'd head right out of the store to the nearest icecream shop for a sundae if I felt hopeless, or to the pharmacy for some protein bars to shift that problem area, if I felt hopeful. When all I really needed to do was say - that's a shame this style doesn't suit my body shape, I'll keep looking for something that does.I know most women say instead: my body is at fault because it does not fit this lovely thing I want to buy.Funnily enough this only became an issue when mass-market clothing became common, during the early 20th century. Before that most clothing was made either at home, or by the local dressmaker or tailor. It didn't matter then what your size or shape was, the person making your clothing simply measured your body, and made the clothing to fit. There was no "Official Body", as Naomi Woolf calls it.Governments the world over are trying to find a way to get a manufacturing standard that will actually work. It is now possible to laser-measure in specially-built booths, the body sizes of thousands of people across the population; translating that into manufacturing will be the trick.And it is also the key to helping women stop finding themselves wanting, when the clothing sizing is really at fault.A recent Spanish government study (the largest of its kind in the world) found that 4 in 10 women had trouble finding clothes that fitted them properly, and that women aged 19 - 30 had the most trouble, because the clothing was usually too small! The government is introducing a new standard, and their clothing labels will now report the design size for height, hips, waist and chest.Mostly what I'd like you to take from this reading is - you are unique. Your body is unique. Your unique body was formed singly, uniquely. It was not mass produced. There's nothing unique about chain store clothing, it is mass produced.You probably will need to look in a few shops to find something to fit you, and that's not your fault, there is nothing wrong with you. The only thing you need to change is your expectation that you need to change anything, let it go.... and be gentle with yourself while you learn to do that.