Probably unusual, but about 10 weeks. It was a niche market paid iPad app, written and deployed in 6 weeks, and we saw immediate sales so we left off iOS contracting and began working on it full time.

That was a little more than 6 years ago and it has continued to be our full-time project. However we did add versions on most other platforms and a cloud sync service, and I'm not sure that we would've continued to generate good revenue without those additions.