Joe,
I find it hard to keep my left arm straight while I swing. I am right handed. Is it bad to bend it a little bit so I can take a longer backswing?
Alex

Hello Alex,
A bigger shoulder turn should help. Keeping the left arm straight accomplishes two good things. It assures the widest possible arc, and the wider the arc, the higher the clubhead speed. It also assures a more consistent arc, for example, if you allow the left elbow to bend, you have to be consistent in how much it bends or else the arc will be inconsistent, and therefore your ball striking will be inconsistent. In your case, as well as many other people, your body build will not let you keep it perfectly straight without restricting your backswing, so just keep it comfortably straight and you should be OK with a slight bend.
Joe