What distance do you plant evergreens for a hedge?

Depends what kind of evergreens, and whether you have more time or money.

Most evergreen shrubs can be planted right next to each other for "instant" hedge. They grow into a unit almost at once.

Or you can see how wide they're get when mature, and space them out so it will take fewer plants, but that they'll eventual fill in in several years. Your choice.

Yeah, really depends on ultimate or 70% ultimate size. Also be aware of their front and back room. If grown too close to a property line, the neighbors may resent the intrusion and legally remove branches over their property. Give your hedge room forward and backward as well as between plants.

You have to look at the full grown width of the plant. Most people plant them too close together when they are young and they are crowded together when they mature. If a plant will be two feet wide at maturity you would want to dig the center of the holes for the plants two feet apart

It depends on the evergreen and the ultimate height of the hedge but as a general guide 2ft apart.