I was having a problem that with every time I would go over a bump, there would be a loud squeaking noise coming from the drivers front wheel area.

I took it to Toyota and they said the Strut had gone bad and needed to be replaced. It only has 10,000 miles on it. What causes a strut to go bad?

 

I think your dealer misspoke. That strut was bad when the car was built. A strut will last in excess of 100,000 miles unless you drive your TCH like Steve McQueen drove his Mustang in "Bullitt"