If you need to do it on a budget, check with Kent-Moore or OTC (Or Gates and the belt makers) and see what alternates they have to the fancy electronic gage - tension is tension.
Sometimes you need the exact tool like a UniSyn for getting multiple carbs to draw properly, but they make enough of them and the price gets into the "reasonable to own" range. And sometimes they come up with a less expensive way to do the same thing.
You own the car - buy the special tool and keep it in the trunk toolbox.
Even if you take it to the garage, some of those odd special tools aren't in high demand anymore or only fit ONE model of car, and the random mechanic you need on the road might not have them. Timing lights, yes they still get used - But not the special one with the dial to adjust it for the proper BTDC offset when you can't see the marks well enough. Tach and dwell, the special tool to set the points, the special sparkplug socket to get around the obstructions... Carry your own.
Even if you hand them to a random mechanic and say "You know how, here's the tool - Go to it."