Simply depends on what kind of work you are doing. If you need one, you just cannot do without it, but its not often you need it. If you are working heavy equipment, tractors, etc, you just might find a use for it.
At work (heavy aircraft maintenance facility) we have a roll around cabinet. On one end of it is a home made bench top hydraulic press using a small porta power cylinder, and on the side is a mounted hand pump. Open the lid, and you find a whole assortment of large and small cylinders, hollow (pull thru) cylinders, and a bottom drawer with assortments of threaded rod in various sizes and lengths, large machinery nuts for the rod, and different metal plates with holes for the rod. This kit is invaluable for removing all things frozen and rusted in place. It has a mile long hose so you can carry the cylinder up to your work while your workwith stands down below to operate the pump.
I'd like to have one of these sets, but cannot justify the expense, given that I rarely would use it.
Charles