I found out about Boggs from a plane maker, who used to send them new files to sharpen before he used them on his hugely thick irons. This was back before 2003 I think, so not sure the quality of Nicholson at that point.
Boggs is not local for me, but I used a USPS Flat Rate puzzle box @ $20, and shipped them 42# of files, taped to a board so they didn’t escape. These were mostly vintage files, bought at garage and estate sales, some NOS that weren’t stored the best, but a variety of shapes, round, square, pillar, needle, cant saw files, knife edge. Not the normal stuff you’ll find at HD.
Needless to say, it was expensive. Total bill for 128 good files was $210, the 120 crappy, “don’t send these in to us again” was $30, plus $45 return shipping. Total turn around time was under a month, just based on photo dates. Part of that was phone tag, as I was traveling when they called me with the bill.
But, can you buy a single 8” flat ******* file for $2? Much less one of decent quality? I use the crappy ones for stupid around-the-shop projects, drawfiling etc., and keep the better ones for saw sharpening, more major work, and then put them aside with other GS finds for the next order going to Boggs. I’m hooked, and probably set for life, but I’m not a serious metal worker, so your mileage may vary.
And previous advice I had seen on saw sharpening was to only use a triangle file once, and get one big enough that you can do two passes on each face, so three saws per file. I think that was from Pete Taran, founder of the Independence Saw company.