IRR, and everyone else,. .. .Thanks for all of this. I have a well used IR, but its lying dormant just now. I have absolutely no intention of waking it all of a sudden and trying to be a smart ass. But, how long can it be dormant before it becomes totally invalid? Or should I be going out, with an instructor, for some torture, shooting some approaches just to keep the paperwork healthy, then allowing it to go to sleep again, until I really get back into using it, ie, go back to work?