OOC: For the sake of not having you casting spontanteously, like a Sorc does, you should probably post the spells you usually prepare on an average day, and then when we wake up after a rest, if you decide to make any changes, post what changes you've made for the day. That way, the DM knows what spells you should have on an average day, and on a day where you change it, so he can keep track.
That's what I did with mine. As a Druid, all the spells on my list are open, so I just posted the ones I usually prepare, and how many of each.