It mostly depends on how like to travel. If interested in finding more about the country and its culture and find your way easily through cities, having a good proficient and professional guide will be great. While having a good one can be enjoyable, a bad amateur one can be such a kill-joy. Have a look at our list and see Iran Travel professional tour guides and guide drivers.
Although it would be great to be accompanied by a tour guide, it is not must except for American citizens. Due to the disputes between the two countries, American citizens have to be accompanied by a tour guide all the time, even if they are traveling through the cities.