Random Thought of the Day: Hours Developed vs Hours Used

I was talking with a project manager about deploying a beta version of some software today. I don't know if this is a well known fact in the software development world or not, so don't shoot me if it's not original.

In any case, I realized that at some level, the usability of software is related to the number of hours it was developed vs. the number of hours it's been used in production.

If a piece of software took 1000 man hours to build, you probably don't want to be using it until there have been 2000 man hours of use. It takes about that much time for the different use patterns to flush out the bugs that affect them. That's not to say that there aren't still lots of bugs -- it's that they live in less frequently used parts of the software.

I wonder what the hours developed:hours used is like for any given version of Windows at the point it's first service pack is released?