4 times a day may be ideal, but as a practical matter most people find it inconvenient to take vitamins a few times a day. I take them after meals. So if I eat twice in a day I take them twice, if I eat 3 times a day, I might take some supplements 3 times a day. Some people also get stomach irritation when taking some supplements on an empty stomach. Vitamins are also better utilized if taken with foods. Think of vitamin and mineral supplements as being food concentrates.