We started talking about it in October of 08 or so, aiming to replace one small, expensive piece of hardware (a UDP-serial bridge, in effect) with some software; by December or so we decided to replace the whole system. I built a very initial prototype by March 09 or so, showed it to some key people, then trashed it and started work on what became ModuLock. We arrived at a rough version of this around March of this year, and installed into our first (beta) property in May. So to answer your question, something like 21 months since conception and 15 months of development and testing for the actual product.