As far as being expensive, it's all relative. I know a guy who's a pilot (I believe he was trained as such while in a military branch) and had a part ownership of an airplane. Airplane ownership got too expensive, so he sold his share in the airplane and bought some machine guns.
Having multiple machine guns of different types, and different accessories and/or add-ons for each of the multiple machine guns is a deterrent to boredom.
MHO, YMMV, etc.