For a hardened steel die , life expenctancy could be anywhere from a few thousand to 20,000 strikes, but even one mistrike could ruin it completely.
A work hardened early tool steel in a drop hammer would should manage about 5,000 strikes before showing wear, but cracking is a hard factor to predict until the late victorian period when tool steel becomes far more quality controled.
Quite often the die (female) is hardened and the male (punch) is iron or case hardened steel rather than a tool steel, so it will slowly adapt to the changes in the actual die with wear and resist shock impact better.
Lettering in dies and buttons was not always cut by hand but punched (hobbed) into the die while shoft and finished afterwards. Worn dies could be annealed (softened), recut or re-hobbed) and rehardened to increase life.
Large production runs would probably be made using hobbed dies (you make a master set and use them to create working dies) so they become disposable tools rather than assets. (minting is done this way). Often elements in several different dies would have the same hobs employed for similar elements too.
Firmins still have a 1840's drop hammer used for some badges as it actually produces a better strike than a modern hydraulic press, but because it's an impact rather than a squeeze it's more demanding on the dies.
It's interesting that until the 1830's French badges and shako plates are generally made out of a thinner guage metal than british as we had better development of tool steel.
All stamping metal is annealed and pickled (cleaned) before use (often in vacume kilns or under controled atmoshphere). Sometimes it will be struck twice or more with annealing in between especially on deep or complex shapes to prevent splitting and cracking of the stamping.
There's a lot of metalurgy involved in the process as brasses have very different properties even with a very small change in their component metals and often require different ways of working entirely.
Apart from the colour, gilding metal is almost mostly copper (90-95%), whereas a cartridge brass in about 80% and yellow brass 60% and some brasses are actually bronzes in reality.
A good example of die progression is some of the lancer cap plates. There are a few where they rehob an earlier die and then cut extra battle honours into the dies in spaces on top of the old pattern if there is room. The next pattern plate will be done more from scratch because too many elements need to be moved.
It's not uncommon in the jewellery industry for dies to be still in used over 70-100 years later and to only be made from wrought iron.
If you ever get a chance, there's a sliversmith/ die stampers workshop preserved in the birmingham jewellery district dating back from 1880, with a lot of badge dies subcontracted out to them and still useable.
http://www.english-heritage.org.uk/d...ilver-factory/