creatine builds up in your system, to a saturation point.
thus you can load up quickly, or you can load up slowly...the end result is the same.
on average, daily 3g-5g dosing will make you hit saturation in 3 weeks.
I'd say it only takes about half as long to get almost back to baseline if you stop, mainly because your body constantly uses creatine, so if you stop dosing, you lose it faster. while 'loading' you're not only replacing the normal creatine you've lost, but increasing total stores...only makes sense it'd take longer.
I also base this on the fact that I do tend to store extra water weight when i'm on monohydrate, and the last time I cycled off, I lost 7lbs in a week...I'm pretty darn confident that 5lb of that was water.