new vs. used mast

[cwa]

Hello all,

I'm building a boat and starting to look around for the mast & boom.
Any reason not to put a used mast on it?
Just looking for the pros & cons of used vs. new.
Design is for a 46' single spreader rig.
Designer says to build your own out of 5.5" steel tubing.
I was gonna use aluminum if I can find a mast that is reasonable.

Any Ideas?

Thanks,
Carl Anderson