People who love colonic irrigation say it helps with digestive issues and energy levels, along with a general feeling of wellbeing.
Rehydrate! Many therapists also recommend taking probiotics, and avoiding meat for the first three days. You should also avoid alcohol for a couple of days (a bit of a drag, we know). Speak to your therapist for more specific advice.
This depends on your body, and how you take to the treatment, so it's another one to discuss with your practitioner. However, three over the course of a month are often recommended.