I hate shopping for my kids. DD1 is 8 and nothing for age 8 fits her. She's a little chubby but not hugely so for a child of her age and I find I'm buying clothes for her in the age 10-11 bracket sometimes larger depending on where I buy them. DD2 who is 6 on the other hand is tiny - she has no tummy at all - and I'm buying clothes in ages 5 for her.
Same goes for adult clothes - I buy one size in one store and then a different size in another.
I hate clothes shopping.