I take the 180 at bedtime and about once a year, I forget to take it. I always know the next morning that something is wrong - I am so much weaker overall and don't feel better until my 60 mg kicks in. I usually look in my pill container (I fill them up each week) and the pill is stuck in the bottom so I know I didn't take it. Have never had any problems with it and as I said, really know when I don't take it.