Sometimes I look at what a product can do rather than just the cost. It is also why I learned a long time ago to purchase good clippers. I can't answer the question for you. But I can ask some. You currently have two dogs. As you get older do you plan to always have a dog/s in your life? The nails of any smaller dogs I have had (or spayed females) seem to grow faster than the others. I should probably do Remi's every week. And yes I do Josef's before every show but all of them get theirs done at least once a month. It is easier to keep the nails short than it is to try to get them shortened once the "quick" has grown out with the nail....
You can buy a small package of the discs separately. I didn't change out the discs very often. The one I have now has variable speeds but I usually don't move it past 2. Yes it makes some noise, there are probably more expensive ones that are quieter but my dogs all got used to it quickly. Some folks recommend giving a small treat after each paw or nail in the beginning so that some of procedure is good to look forward to. Mine just feel relieved to get free with all four paws attached....
I remind them that they are not being mistreated and they can not call the shelter with a protest....By now they are resigned to the process and suck it up until they can get up and dance across the floor without "clicky clicks" and I tell then how wonderful they are.
Karen just got a battery operated Dremel to borrow and try. Maybe she will shared how it works for her.