Long ago, clothing was made by tailors or family members specifically for a certain person, exactly in their size to fit them. In today's world, most clothing we buy is ready-made, so we need to look for our exact size on the label. However, different clothing manufacturers sometimes use different standards, so it is always best to "try something on for size" in the shop's dressing room to be sure it is the correct fit. In the same way, we now use this expression to refer to anything－not only clothing －that we want to be sure is right for our needs. You can even say you want to try a relationship on for size! It means you want to go out with someone a few times before you decide if you should get serious with that person.

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