No, as long as you take it every day you'll be fine. To improve your odds of taking it every day, it's best to make it part of some other routine. For instance, I take it each morning immediately after brushing my teeth. Get into the habit and there won't be a problem. There's no need to take w/food or w/o food. Just take it consistently and you're set.
Does it matter whether it's taken exactly 24 hours apart? I usually take it as soon as I get up, but as a student that can be any time between 8am and 1 pm depending on what classes I have that day. Perhaps I should be taking it in the afternoon or evening so that I can keep it at a consistent 24 hours between doses...