There's no good reason Smithing Templates should be single-use.

It's crazy just how many diamonds you need for something that's 95% cosmetic if you don't want to be forced to look around for ages for more copies because some are incredibly rare. For one armor set, it costs 28 entire diamonds.  That is two more diamonds than it costs to make a set of armor.

This gets extremely ridiculous when you want to add detail to early game armor, but don't want to use up any rare templates you find.  To decorate copper armor, you basically have to make diamond armor, and at that point why even bother trying to make early game armor look nice?

It's also another reason on a pile of reasons why people go into huge despair if they permanently lose their gear. The time and resource investment is just too high for something like this.  Not to mention it encourages hoarding rare templates on multiplayer, meaning new players have to go even farther out to get some templates, or they may not even get any at all if the world border is small enough.

Smithing Templates really should be infinite use, with the option to duplicate them still there for sharing reasons.  It should not be this expensive to decorate armor.