Remember the Snoopy Street Party that I have posted here well my wife and I did get something new this Christmas for the kids, Snoopy shirts. One for Maki and one for Gelo, my wife and I wanted them to look good and in uniform unfortunately both there size and designs were different. So what we just did is that we tried to look for the same color even though the designs are somewhat different.
Buying shirts without the kids is hard and basically it was all assumptions based on their age. Thankfully shirts varies according to age sizes. So if you just tells the sales lady the age of your kids instantly they will reply to you on what size of shirt your kids should have but of course it will still be based on your guessing. They are your kids so you should at least know their sizes eve though it's not based on their actual sizes.
Shirts are the only item that we bought for the kids because buying pants without the kids would only waste time and money. It is much better to have it fit to them rather than do your own assumption.
If you want or if you have a tape measure with you in the house you can have it measured before leaving the house. Then you can just ask the sales lady if they have that size. Simple isn't it, just make sure to plan your shopping on that day.
How about you? How do you buy your kids clothes? Do you bring them with you during shopping or you just basically do a simple assumptions of their sizes? Hope you could share some tips.