Thanks for the tips, ejagno!
I have the report back from talking with our house insurance guy about potential credits for improvements we've done. We got a reimbursement check for $174.00. (I believe that is a reduction over the previous year's insurance. Don't know how far back he's allowed to give us credit.) If that is $174 difference per year going forward, though, that's great, especially since our state just agreed to allow an increase in insurance rates (sigh).
Some of the things that mattered: a new hot-water heater had been purchased, some plumbing replaced, the alarms on front and back doors EVEN THOUGH they are the simple, single-door alarms, not whole-house at all. Most of the things, HE prompted me about, because he has a checklist to go down and ask his clients, so that was a great help - I didn't have to try to remember or figure it out myself.
So I would definitely recommend just double-checking when your house insurance premium is getting ready to come due! You never know what you might have done that will impress an insurer!