New school shoes

Went out a few weeks ago and got Lex his new school shoes. He wanted a specific pair of light up ones. These were the most expensive pair of shoes I have ever purchased for him. But, I do believe in buying the kids a good pair of sneakers as they usually last all year long. I told him he was not allowed to wear them until he went to school. He gladly agreed and put them up in the shoe holder on the back of the door and they have stayed there ever since. I then went out about two weeks ago to buy Nate his school shoes. He's starting preschool so I figured it was time for him to get a pair of good shoes too. No hand-me-downs this year. He also wanted light up shoes. He was super excited to see them and wanted to wear them immediately outside. I told him he could not wear them outside until school started, but he was welcome to wear them in the house for now. He refused to do that because we "don't wear shoes in the house, Mommy!" Why is it they pick certain times to listen to the rules????