How long did it take to recover the twin towers damages?

Damage "do" meaning Received or "how much damage it can withstand before collapse?"

It was hit in one place, modern buildings would of stayed up longer or even not collapse, but the designer of it made it with fireproofing foam, which normally is bad, but to make matters worse, the person who sprayed it did a TERRIBLE job, making the towers very vulnerable to a large explosion. Which, as we all know, the terrorists got a plane with the most flammable fuel and stuck it right up into the towers, causing mass destruction.