an AH- HA moment

So, a few weeks ago, Michael and I are at Home Depot (we frequent HD alot these days), and on this particular day, we were in the market for canned lights (recessed lights). We are putting in quite a bit of recessed lighting in our home, so of course we are trying to get the best deal but yet maintain great quality! There are quite a bit to choose from. So, we asked the person in the lighting department to help us, as we had a few questions. So, the HD lighting person kept asking us is this "New Construction" or "Old Construction". We kept hearing this term, and in fact we had been at another lighting place just before this and they asked the same question. Now, for a long time I took this to mean that there was some mysterious date that signified a difference between New Construction and Old Constructions. Nope, that is not the case. This is what they mean when they ask this question: is there drywall in the place that you are putting in your canned lights? That is what it means, your house can 5 days old or 50 years old and that particular question is really all about drywall. This is why this process drives me crazy- there are all of these codes word and phrases I have to figure out. I think it would be easier to ask if you are putting in canned lights in existing construction (not removing drywall and basically just putting a hole in the ceiling) or is there no drywall and you have to attach the canned lights to the beams/wood. Maybe its simple to everyone else, but this particular issue took me several weeks to figure out- then it was like "ah-ha", I get it now!!