Fact: some people will continue to ignore previously stated reasoning for why cdrs cause premature wear and tear almost instant death (not to be confused with instant death a slight amount of extra wear and tear). Nothing will sway their beliefs. Nothing.
Fixed that for you so that it better reflects what I typically hear bandied about by the fear-mongers (not necessarily by you, but by many).
I agree that there may be a slight increase in wear and tear. Not sure why you chose the word premature. The system has wear and tear whenever it is used. Increased wear and tear isn't premature. It's just more. Almost sounds like you were going for premature system death, and it's not premature if it's due to a little extra wear and tear. Premature system death would be "oops, I dropped it". That said, these devices are designed for hundreds and hundreds of play hours. Good CDRs burned well probably have no significant impact on the life of your equipment. If you use cheap CDRs and burn them badly, well, you'll knock a few tens of hours of life off your hundreds and hundreds and you'll end up making repairs just a little sooner than you might otherwise.
Cost-benefit analysis, folks. Very simple. You're all going to have to make repairs at some point because no mechanical device lasts forever, even if well-maintained. So you have to decide if the opportunities you get to play CD games you aren't paying mucho $$ for (or translations you simply can't get otherwise) is worth paying some $$ making repairs a little sooner.
Honestly, if we want to talk about costs, emulate on that PC you've using to access these forums. Download ISOs and emulated them in Ootake or Mednafen (free, both of them). That way you're not putting any wear and tear on your Duo or CD-Rom unit. Heck, make ISOs from your original games and play them on the PC and you can preserve your Duo a lot longer than if you were actually using it. As long as you use your CD unit once a month to keep things limber and the moving parts don't dry up and the belts crack with age, you can preserve your CD-ROM drive much longer by putting almost no wear and tear on it at all. You too can be that old grannie who drives her car once a week and owns it until it simply rusts through.
So make sure you have a good brand burner (they're all pretty generic and capable these days, though), buy good discs like Taiyo Yuden or similar, and burn them at a speed appropriate to the disc and burner (slower will probably yield better results, but your mileage may vary). Chances are if you're getting a stack of 50 discs for $5 and burning them at 48x in that burner that cost you $15.99 at MicroCenter, you'll be making your repairs just a little sooner than you might if you stuck to pressed discs. If you're buying Taiyo Yuden or gold "archival" discs and burning them at the lowest speed supported by the discs and your $50+ burner by a known good brand with good reviews and reliability, I doubt you would really notice any perceptible decline in the lifespan of your CD unit. But even if you're using only originals, you're going to have to pay for repairs at some point. The only way to keep the repairs away forever is to not own the hardware, and then what's the point?