by the way, you didn't ask, but I posted pictures of guitar necks elsewhere and someone asked what rasp I was using to get the necks to be straight without any lumpy bits. I don't know if this kind of thing comes up in furniture that's not turned, but establishing a straight line on a curved surface is better done with something like a nicholson super shear (not a vixen and not a rasp) than anything else. A super shear gives you a flat surface to make diagonals - it may not be intuitive, but if you take advantage of a diagonal on a flat file, you can make very straight curved surfaces pretty easily.
I think it gets complicated to make some things on power tools and a guitar neck like that is one of them. And it doesn't take long to make by hand. I can't think of anything that an expensive rasp would do better, but I did use the gramercy sawhandle maker's rasp around the transitions before scraping and sanding.
when auriou started being sold, it was just pounded by bloggers and chris schwartz types as being must buy tools, but an older rasp seller here who sold mostly to pros gave advice before that to do what I mentioned, use a rasp to establish basic shape and then finish up with files for the most part and limit the use of expensive rasps for bulk work. the idea that the average hobby woodworker still struggling to do joinery efficiently should go out and dump $500-$1000 on rasps was really dumb.
Far different thing if you spend out of want and not need - I do that all the time. Pleasure spending. It's nice if someone making things draws the line where that is and tells people, but it didn't happen often back then, and I guess it really doesn't now, either. I just last week saw the blue spruce "butt chisels" for the first time and it has to be one of the more offensive offerings that I've seen in quite some time. I'm sure they'll be flogged by gurus.
