[scooter79rs]

@GreenVampire, setting the normals angle is a quick way of getting hard and soft edges but it doesn't usually. What I do depending what I'm modeling is either completely hard or soft. With cars or people select the whole object then soften normals the normals accross the whole mesh will be 100% soft and some areas will look like crap from the normals (they did around the arches of the mk2 Escort in the uploaded pictures) now select the edges that you want hard normals on (I.E. Body lines, wheels arches, etc...) basically anything where there is a hard edge on the car in real life, after they are selected go the normals menu and select Harden Edge. This for low poly, if you some where for an edge line to between 100% soft or 100% hard thats when you would use the set normals tool

On the escort model shown here I only used soften edges (across hole the whole car) then used harden edges on the body lines.