When our kids were little we bought their jeans at Sears. Back then Sears quaranteed their jeans to last until they outgrew them. My son and daughter would wear out the knees of their jeans playing. I walked out of Sears several times with new jeans at no charge.
Wow. I wonder if they still do that, runs to sears website. My youngest is terrible when it comes down to that. His knees always get worn out because he likes sliding on things.