Wow, didn't mean to derail this thread by bringing the Chronograph into the mix!!
To those readers: Please go back and read the heading under which I listed the Chronograph = Stuff you MIGHT WANT....
Personally, I used the chronograph as a variation of the ladder test for many years before I even knew what a ladder test was. Across the bench, as I tuned up a load, if my velocities plateaued, then I stopped adding powder. No sense in throwing more powder at it and not getting anything back.
I also wanted to know, even from the beginning, how fast I was flying. Not so I could brag, or try to push the limits, but so I could get an accurate muzzle velocity to cross reference to the ballistic chart (now it's all calculators) to build a preliminary range card.
For a $100, a pro-chrony was probably one of the better investments I've made. Rather than shooting more money (aka rounds) downrange to determine my range card, the chrony gives a good ballpark to get me on the page as I move further out. Saves a lot of money over the years in components (bullets, powder, primers) and brass life.
So no, it's not a necessity, but I still think it's worth having on the list of something a new reloader MIGHT WANT. He11, I'd rather have a chronograph than an electronic powder scale or powder despenser anyday.