I kinda did this. I wanted my girls to match every day while down there. So, since they didn't have many matching outfits, it meant supplementing their current wardrobe. But they both needed a few more summer outfits anyway, so don't feel bad really. The older dd had a Minnie dress, bought a Minnie dress for the 2 1/2 yr old dd. They both have denim shortalls, bought them matching shirts to go with them. They had about 3 matching shirts, bought them shorts to go with those. And matching swimsuits too, btw.
To me it makes it easier to spot them if they are matching, makes for cuter pictures, and the girls LOVE to match. And they will wear them all summer so it's not a waste. Except the Minnie dress maybe, LOL.
And I bring a stain stick (shout or spray and wash) with me on all vacations. If you treat the stain when they take off the outfit for the day, even if you dont' get to it till 10 days later it will come clean.
Nora, only 11 more days!!