It's really difficult to find a decent file these days.
One thing most people no longer understand, is how to use a file properly.
I had to take my grandson aside a few days ago and show him how to use a file properly, store it properly and clean it properly.
A file should never have pressure applied to it on the back stroke. Apply pressure on the FORWARD stroke only. LIFT the file off the work for the back stroke
Applying pressure on the back stroke will cause the cutting edge to "fold" and no longer be able to cut as the cutting edge no longer has the proper angle to bite into the material being worked on.
Often, especially with soft materials like aluminum or brass and even soft\cast steel or pot metal the material removed will "stick'' to the file, being jammed into the grooves. You need to remove this buildup as it gets progressively worse and ends up marring a relatively smooth surface, requiring extra effort to finish properly. You need a "FILE CARD" to clean out this buildup regularly.
Some folks use a wire brush but that can cause issues as well with the sharp edges. Don't use a wire wheel on a motor, that will ruin a file on the first pass.
Proper storage, where the files don't touch each other and won't rust is also very important.
If possible, files should be in a drawer, not touching. When files rub against each other, they dull or get chipped. Hanging them separately works as well.
Files should be cleaned before storing and a quick wipe down or blow down with compressed air will usually do the job.
Make sure to keep the files DRY. RUST destroys the cutting edges on files.
If you plan on storing the files for a few months, an oily rag or even a light coat of varsol before putting away will keep them from rusting.
I buy my files from the UK, Tracy Tools.
Canadian Tire, Princess Auto etc do not carry good quality files.
I have files I use regularly that are 20+ years old and they still cut just fine.
Files like Faust, Starret, etc are very good and will last a long time with general use and proper care.
When I was still on the job, there was a part of the factory where files were being used constanty by people poorly trained. They went through a lot of files.
The "operators" would apply pressure both directions, and only use the front 5 cm of the blade. I'm talking about 30cm blades and 12 cm blades mostly.
Expensive files, that were often thrown into the scrap metal bins after a single day of use. Mostly Nicholsons.
Being the scrounger I am, I would rescue these files, clean them up and take them home. I still have a stockpile of those files. Of course that was an unusual situation, but well worth taking advantage of.