I have been taking lithium orotate for many years now to treat my bipolar disorder. Currently, I take 3 pills of the Vitamin Research brand of Lithium Orotate. Each pill contains 4.8mg of elemental lithium. I take 2 in the morning and 1 at night. I don't know if a split dose is necessary - it's just how I've always done it.
If I miss a dose, I usually don't notice anything. I only start getting increased symptoms if I go without taking it for a couple of days. So I think it has a fairly long half-life. But that's just a guess.
I have previously taken 4 pills a day, but now I can manage on just 3. Some of this might have to do with the fact that I've lost some weight. There are many medications where the required dose depends on body weight, and it's possible that lithium orotate is one such medicine, but that's also just speculation.
Lots of medicines require regular dosing before the full effect is felt. If this holds true for lithium orotate, the full effect might not be felt until taking it for several days to a week. I try to stick to a regular schedule. I use a pill box to help me to remember to take it. It also prevents accidental double dosing. I have in the past taken the Advanced Research brand and the Doctor's Best brand (now discontinued). I've noticed no difference in effectiveness and usually buy whatever brand is cheapest. Both the Advanced Research brand the Vitamin Research brands have some quality control issues. Occasionally, the Advanced Research brand had broken tablets and the Vitamin Research brand has crushed capsules. Not a huge issue, but something I would be amiss to not mention.
The dosing for lithium orotate can be confusing because there are two numbers that are usually listed on the bottle. First, there is a higher number, like 120-130mg, which is the amount of lithium orotate in each capsule or tablet. Then, there is a lower number, usually around 5mg, and that's the actual amount of lithium. The orotate molecule that the lithium is attached to is heavier than the lithium, and that's why you only get about 5mg of lithium from a 125 mg pill.