Ideally it is split as far as part as possible, but you have to work with what you can. When DS was little he had his morning at 9ish and night at 5ish b/c he needed to have an empty tummy b/c of bad acid reflux. Now it is more like 8ish and 8ish. It varies over time. Also, you can do the inhaller right away and the taps a couple hours later if that helps get the inhaller spread out more--at least that was what we were told--but we do a nebulizer and not an inhaller and that last 4 hours with it peaking in effectiveness about 40 minutes in, with a bell curve of the benefit from themeds. Maybe ask the pharmasist or dr what the inhaller dosing kick in is, i.e. how long it last when it peaks and then if you do that right away and taps later within that time frame. For the first 2 years you'll end up having a new routine almost every 3 weeks b/c of eating, sleeping pattern changes. Hope this helps.