Whether jail time for your first DUI will be a part of your punishment will depend on many different issues, including whether your arrest is for a first-offense misdemeanor DUI or an excessive DUI or a felony DUI or a felony aggravated DUI, meaning you caused great bodily harm, permanent disability, or permanent disfigurement to another person as a result of your impairment. Generally, the more severe the charge the greater chance of jail time.