I would like to know the recommended temp spread on a digital A/C thermostat. I believe it to be three (3) degrees. My son has one which he says is set for one (1) degree. Isn't that a too tight spread setting? I would think it would cause the A/C to operate too much of the time.

The closer the differential , the more the A/C will cycle which is not efficient, normally two degrees is normal but three degrees is good as well , the difference is the temperature swing.(if it does not bother you then it is fine) One degree is pretty tight causing a lot of cycling.