Don't feel bad. I did the same thing to my kids, except I made them buy back their stuff. Anything not bought back after 3 months was donated to the Good Will.
Years later they realized that I put the money they paid me for their stuff back in their savings accounts. Buying back their stuff...Free. Learning to pick up after themselfs...Priceless.
Hang in their long enough and years later you might hear a thank you mom.