As others have pointed out, it is easy to test a square. If it square, it is square, and then the only other considerations would be:
* Utility to purpose - Some squares are more suitable for some uses than others.
* Styling or fashion - does it look good or feel good in the hand.
I have a bunch of squares of different types and sizes. I suspect it is true for most of the people here. For basic woodworking, I use the Starrett combination square the most.
I have a Sorby "Gilt Edge" 9 inch try square that was tossed in when I bought a used bandsaw. Besides being perfectly square, it is a work of art. The brass, wood, and blued steel give heft and feel good in the hand to use. Working with it feels better than the combination square, although I can't really explain why. Perhaps it is the wider blade.
I would love to have a 6 inch try square just like it, and maybe I'll find one lost in a bin somewhere. Do I really need a try square, when the Starrett combination square will do just fine? No. Do I enjoy using it? Yes.
Last edited by Tool Agnostic; 03-08-2019 at 01:53 PM.