As I've found out once the hard way, most Dremel Tools are not that "heavy duty" to be subjected to hard use.
As I mentioned earlier, polishing or sanding small parts, and under use load for short periods of time, you might be OK. They are basically designed to be a small arts and crafts tool.
But try to use the tool for a job that it's really not intended for, let's say using the tool as a Roto-Zip Tool, grinding metals, large jobs, the tool will likely fail. Sad thing is, some of these Dremel Tools are pretty costly.
I screwed up my $100 Dremel once, trying to use it to enlarge a hole when installing a door knob-lock on a metal laminate entrance door to the house. Luckily I was able to buy the part that failed, a splined plastic Tube that connected the Motor itself to the Arbor-Chuck on the tool, and for $11 plus the shipping, the tool was repaired.
If you already have a DA of some sort that can be adapted to use a smaller Plate-Pad, that would be the best way to go IMO.
In instances where headlight lenses are really buggered, so badly yellowed, cloudy, and the UV Coating is essentially shot, one commonly has to resort to sanding papers beforehand. Progressing to finer and finer grit.
The choice of what grit is always an unknown when you start. 600-800 papers might get it as a starting point, but then again maybe not?
When finally getting down to 2000-3000 and such, then much less work would be needed as far as polishing with compounds-polishes to finish.