We purchased our screen doors about 8 years ago and never had problem with them. Our dog does not see too well and heard another dog barking so he ran at full speed into the screen. I thought it was broken but I just opened it and closed it again and there were no problems. We even had someone try to get into the house and messed up the screen on the front door. I just took it apart and put it back together and it works perfect. After 8 years the string finally broke so I will be replacing hopefully the string only. We will see how it goes when I try to replace the string.