So I used to use a macro to announce to raid when I applied Pain Suppression or Guardian Spirit to a target, with a countdown to expiration to enable tanks and other healers to know that it is up and exactly when it should expire in order to facilitate chaining of CD's when necessary (very handy when dealing w/ enraged shamblers on H LK).
There were some potential problems with using a macro, though: it would still announce even if the spell was on CD, the target out of range, or target out of line-of-sight, leading others to think a safeguard was in place when it wasn't; it would sometimes spam raid if I hit the button a few times under the logical operating theory that if you hit it a bunch of times it would work better; and in the case of GS, it would not indicate if it was removed early by actually saving the target's life via a proc'd heal.
Couldn't find a mod that would handle this the way I like (some announced application and expiration, but nothing to make synchronized chaining easier), so I did what any other industrious programmer-wannabe would do: I begged for help. The credit for the following addons belongs 100% to Treeston, one of our moderators in the Interface and Macros forum. They work flawlessly and I thought some of you might find them useful as well, so figured I'd post them here (you can see the code, etc, in the original post here).
PSAnnounce will announce application of your PS on target and count down the last 3 seconds till expiration.
GuardianSpirit mod does the same for GS, but will cease the announcement of any remaining seconds and instead announce early expiration if the heal is proc'd.
Both of these base their actions off the combat log, so there are no 'false' notifications, and at ~ 1kb each aren't taking any toll on your memory resources. To use, simply unzip the folders to your Interface>Addons folder and you're good to go next time you start up WoW.
@ Treeston - thanks again!