Well, I think you would want to clean anything weekly, if not more, anyway. I use a great cleaner off amazon, and it is cheap and smells good, and safe for coated stones. I clean my rings after each day I wear them.
http://www.amazon.com/Caribbean-Banana-Coconut-Jewelry-Cleaner/dp/B001TQ41VI
All rings, regardless of stone, will get gunky, and mineral deposits from water build up, making everything sparkle less or look dull.
Now it is true that sapphire will not sparkle like moissy, but it will have a pretty glow and there are a lot of colours out there. You might just need to have some time to wait while the right stone finds it's way to you.
Moissanite is always a good choice too though.