My uncle swore I'd never build a deck without a miter saw, and the old guys at the lumber yard backed him up
Back in 2009 my uncle handed me his 30 year old circular saw and told me a miter saw was a waste of money for a first deck. I believed him for about two weekends until every corner joint on my stair stringers looked like a beaver chewed them. A guy named Ray at the lumber yard on 5th street watched me load crooked cuts for a month, then finally showed me how he clamps a speed square and cuts by eye. Ended up buying a used miter saw for $90 and my next set of stairs came out clean on the first try. Anyone else get handed bad tool advice from family that cost them more time than money?
Did Ray ever explain why cutting by eye works better than people think? In my case the jump was not the saw itself but learning to mark both sides of the board and check the square before every cut. Your uncle was half right for framing lumber where a fat gap gets hidden, but stairs and railings show every gap. Speed square and a sharp pencil fixed more of my cuts than any tool ever did.