I had used weakauras under my character on the screen. Used a rune texture, displayed the text in the center and if it expires, the sonar sound comes up. It's very comfortable for me to hear a sound if i'm busy, instead of moving the eyes constantly from the showdown to check statuses etc.
CLC Ret is probably the best add on you'll ever need to play a Paladin. Covers all the basics and timers. Paladins were changed quite a bit during Cataclysm to be more of a prioritizing rotation depending on what comes of CD and what not.
And then keeping track of inquisition was a pain. And even after actually keeping track, it was hard trying to find the perfect time to refresh it. This is what CLC Ret does.
It not only tracks the buff, but gives you the best time to refresh it. Early on, I would actually simply look at the add on and follow the rotation. Now that I am so use to the class, I know when to it what, and only really look for Inquisition refresh.
Tellmewhen, configured the Inquisition icon to work only in combat mode, so when the buff ends, a very big icon of inquisition appears that covers my character until I restart Inquisition (and then it disappears until it eventually ends).
This is what I see when I am fighting (If not fighting and inquisition is absent, I don't get that on screen of course ) ... as you can see, it also tracks foj, goak ... availability AND, when it occurs that 3 stacks get me an instant flash heal, the icon pops up too ...