Tachometer install?

I got a ‘72 chevy c10 from within the family a couple years ago. Put a lot of work into it and also had my mechanic do a couple more complicated things (tuning the quadrajet, hei distributor).

It is almost entirely stock, but did not come factory with a tach.

I think I want to put one in. Is this useful/a good idea, or unnecessary? Also, is it something a driveway mechanic could do themselves? I know my way around cars, but have yet to open an engine block or mess with wiring.