In my experience of steel frets for guitar I have seen many types, some named & nbsp; “extra hard”, other “stainless steel” & nbsp; or others. The problem with steel is that it can have different hardnesses, depending on its code. Some fret makers are content to use “soft” steels while others use truly hard metal grades.
I use Jescar fret Stainless Steel, & nbsp; they are by far the hardest and have a well usable stem on vintage or new guitars, you can find jumbos of all sizes.
PRO : The steel keys, well placed and ground without exaggeration, can last an eternity. I have not been able to verify in my experience, but I think they can last up to 6-10 years even in the hands of a professional, who devotes 4 hours a day on the instrument. 18% nickel frets can groove after 6 months of frequent use. I remind all guitarists that the frets are damaged sooner if the guitar setup is not correct.
CONS : the cost of labor, since the key at the end costs little more than the nickel alloy key. Labor is very expensive because the work is longer, more tiring, requires dedicated tools and methods.
Some key change operations with steel on Suhr, Fender, Ibanez. Our C-Reptilia Masterbuilt also has gold steel Jescar keys.
If we consider the cost of multiple key changes over the years due to soft nickel frets, steel frets are ultimately worthwhile. On our price list you can find the price of these operations, you will make a idea.
One observation, on a bass I wouldn’t have steel frets. The wear in the bass is less, for two reasons: the techniques used (few bending) and the diameter of the strings.