He is right in a sense you know. I would not try and use them unless you really need them. Take a crown prep, to do and occlusal reduction and the functional cusp reduction and facial and lingual wall reduction you wouldn't need any magnification, however on the mesial and distal if its bordering a tooth, then mag is good so you don't hit the adjacent tooth, and then to chamfer margins I use my magnification because the margins are so critical in a crown!
Bill, He is right though about not having your loops, I have seen many people forget them because they have worn them out, trust me you get used to having glasses on top of your head, and I have seen many peoples break, usually the band or the glasses, not the loupes themselves. You don't usually wear any other piece of equipment, esp not an amalgamator.
So in other words, he is right in that you should be able to do your preps without loupes, but they are a great tool and in a few cases, can help a lot. Just don't depend on them for everything, or it will bite you in the ass later.
BTW, I have microsurgery 3.5x wide field loupes, great loupes, but a slight bit on the heavy side for my taste. I just got these, I had orascoptic and did not like them at all!!!!!
PS how are you needing loupes right now anyways? Aren't you just starting dental school?