The best solution I ever found was a lubricant that the local garage door
installer sold me. Depends if your climate is an issue but where I am, this
stuff stayed pliable to temps 20 degrees below zero. Sorry don't remember
the name, but it was sold in a small squeeze tube, small application in each
hinge did the trick for years.


This grease is compatible with plastics

http://www.lubriplate.com/webstore/detail.aspx?ID=14