My husband is 6'4" and our standard shower arm situation is not working very well. I bought an extension arm from Home Depot so that it will come out about 5" higher than where it comes out of the wall. Problem is, it is really hard to unscrew and I am worried it may be rusted... and then I will break it off in the wall. Is this an urban legend or can I assume that it is just on there tight because the house is 38 years old and it is most likely an original fixture?

It is most likely OK to unscrew the old shower arm. They used to be made with lot heavier pipe than they are made today. Use large channel locks, grab it as close to the wall as possible and turn it. Do not apply pressure sideways. Try to turn it around its axis. Let us know how you did...

The shower will be chrome plated copper. The fitting that it screws into will most likely be copper. Copper tarnishes but does not rust. While it is possible to break the arm off, it is unlikely.

Put pipe wrench on the shower arm close to the wall and turn.

When installing the new arm, coat the threads with a generous amount of pipe thread sealant, commonly called pipe joint compound. Screw the new arm in as much as possible by hand.

Assuming there is a bend in the new arm. Insert a long, large screw driver in the arm. The screw driver will lengthen the arm and increase your leverage. Tighten by rotating the screw driver in a circular motion. Using a wrench on the outside of the arm will scratch the finish.

Remember the arm must point down. After each turn you must decide whether you can make another complete turn.

Ewww, good answers! Thank you very much. Need to go buy the proper tool, aka channel locks, and then I will try my luck. I will keep you posted, thanks again.

On top of both experts advices I will suggest to apply some WD-40 at the end of the shower arm where it goes inside the wall let it soak for a few minutes, then try it,thanks.

John