I am thinking it would only take you 30-45 days to accomplish a gold set of crafted jewelry if you really wanted it and prioritized it. You could do it casually if you had 8 characters ready to be doing daily writ quests. Completing the daily writ quests for all crafts on one character nets you 4.4k gold, at 8 characters that 32.5k a day. So, over the course of 60 days completing simple writ quests you could easily save up enough cash to buy the gold tempers. Although, it's unlikely you will only be doing writ quests everyday; you could spend the rest of your playtime harvesting ingredients to maintain resources for the writs, and sell tempers you get from refining those ingredients for other crafts, and keeping the jewelry crafting ones. All in all, I think that is pretty fair to have what is potentially the best jewelry you can have in the game. I would say it's too easy, but there are too many sets, and part of the fun in the game is mixing and matching sets.

Granted, this method would be a lot harder to do for a new player, but there are other, faster methods that anyone can do.