I was only ever on regular Lithium very briefly (a few days) before a hospital psychiatrist switched me to the extended release. It was about 13 years ago. I don't remember details, but I do remember telling the psychiatrist that I was happy with the switch. I did, however, still get plenty of side effects from the extended release over the years. Not everyone experiences bad side effects.

Perhaps some people have to take the regular Lithium three times per day (depending on the dosage). I never took the extended release more than twice per day. Twice per day is really as often as I want to take medications. When dosing is more than that I often forget the mid day med(s) or just feel overwhelmed by the frequency.