Me too. I started saving them, even the old yellow laminated cardboard ones whenever I junked a timer. Since Intermatic is about the only timer brand that we ever see in these parts, they all seem to "fit" somehow.
I am now seeking the plastic guards for water heater thermostats, since those also tend to "disappear". I cringe when I open an access panel and think of Harry Homeowner going in there trying to save a few bucks on his electric bill. These things always seem to be missing and the quarters are much tighter.
