I'm preparing to install a new garage door opener on a 2-car garage
with roll-up metal door. I'm concerned that the door may not be
properly balanced, and that may have led my old opener to wear out (it
was a 14-year-old Stanley, so it may have just been old age too).

The new opener instructions states that if I open the door 3 to 4
feet, it should stay open. My door will stay open if I open it about
3 1/2 feet, so it meets that criteria. But when the door is fully
closed, I have to pull pretty hard to get it to start to open, and it
only starts to get easier when I've raised it a couple of feet. I put
my bathroom scale under the door, and I weigh 35 pounds on one end, 42
pounds in the middle, and 44 pounds on the other end.

does this seem normal?
thanks,
paul