My coop isn't finished yet, but when I finally get chickens I think I'm going to use the deep litter method and clean it every 6 months (March and September, most likely) along with scraping the poop board every day or two.
My floor on the inside run is cement as well so I could probably get away with monthly-- but I do it weekly for now. The outside run though, probably once a month is enough since they just naturally turn it around and mulch it into the chips and dirt. As for the coop and the "deep cleaning"/ mite spraying etc-- I'm thinking I'll do it twice a year, Spring and Fall. Of course I've only had my hens for a few months now... so pretty new and may decide different in the future!
Twice a year works well for me too! I do it as soon as a warm weekend hits in early spring and then late fall before Winter approaches I do it again! We have a wood floor and I use wood chips. I use stall dry now PDZ to help with any odors/keep things dry but otherwise use the deep litter method and it works good for us!