Yes.
Yes.
And Yes.
Most people on the forum rate the manual CCT's such as APE ones from the states, or make their own version. Just search for thread with the word "CCT" or Tensioner" in the search box above.
There's also a great sticky above this post which tells you how to fit them.
Apparently you sometimes get a rumble before they go, mine have gone twice now and I never heard a thing. (The straight-through carbon race cans might have something to do with this).
Doesn't seem to matter what colour spot they have on them.
It's usually the front one that goes, allowing the exhaust cam to jump a couple of teeth or more which lets the exhaust valves become acquainted with the piston.
Not a hard job to fix, rare that the piston is damaged and all you need is a head gasket, new CCT's, a pair of exhaust valves and a few hours work. The first time it'll take you all weekend, you get better with practice, especially if you have an assortment of spare shims.
If any of this doesn't make sense, you probably aren't mechanically inclined to get down and greasy with your bike engine, and so it's best done by a workshop.
But Yes, they need changing.

It's not falling off, it's an upgrade opportunity.