I've heard they cure the common cold

but seriously, it's more for color and alignment issues (not screen burn or "gaussed" monitors. If you're colors are solid (not washed out or weak) and the picture is where its supposed to be, then you are likely fine, you might not even notice the difference. I just did a cap kit and after you get up the nerve to discharge the tube ,its really a piece of cake. Hell even the discharging wasn't that bad--it's like any dangerous task, if you pay attention and aren't a dumbass , you'll be fine.
If you know the chassis manufacturer than getting a cap kit is pretty easy--www.therealbobroberts.com seems to be the defacto expert on these things and an excellent guy to deal with at the same time. Hope that helps.