This is my truth and my truth may be different than yours but...
After that infamous MMO Champion article (that I won't bother linking to) a lot of people thought they could make big bucks with Inscription. Mind you, these were people who either didn't have Inscription or had it at a very basic level. Although a lot of gold can indeed be made from it, arguably making Inscription the most profitable profession of all, there's a catch. Or several, if you will.
I was fortunate (and perhaps insightful) enough to have learned Inscription as soon as I created my first Death Knight, right after I got the Wrath of the Lich King expansion. Back then, it wasn't immediately clear that this would become one of the greatest money-earners in WoW for a lot of enterprising people. Notice I'm underlining the word "enterprising" because the entrepreneurial spirit doesn't reside in everyone. There are plenty of Scribes (not Inscriptionists or Inscribers or other wacky names) that barely get by.
When the WotLK expansion was released, it wasn't cheap to level Inscription. Those who prepared beforehand (by hoarding various kinds of herbs) leveled it for cheap. Others, not so much. As anticipated, entrepreneurs had bought massive amounts of herbs before the expansion when they were cheap and sold them to new Scribes. These people made a killing.
I like to anticipate what I will do in the future so I had lots of herbs of all levels in my bank. As a consequence it wasn't hard for me to level Inscription although occasionally it was frustrating. At various times I would find myself without enough herbs, or needing just one more ink, or trying to stretch that green glyph as much as possible.
It's fine and dandy to level with trainer-bought glyphs but at one point you will have to engage in Minor Inscription Research, and later in Northrend Inscription Research. These are essential both for continuing your leveling process and more importantly for allowing you to discover powerful new glyphs that are not available from the trainer. I won't go into details here because I don't know exactly myself but an accomplished Scribe needs many weeks to research all the glyphs.
Are you still with me? Good. Let's say you've finally researched all glyphs possible. How will you know when to stop researching? At some point you will stop discovering new glyphs, BUT be careful here because sometimes towards the end of your "studies" there are days when you won't get a new glyphs. However, researching again the next day will render a new glyph. To be certain you got all, take the plunge and sacrifice some resources for a few days extra after you stop discovering new glyphs.
So now you're researched all the glyphs. It's all good but you're far from being a master. Patch 3.1 (or 3.2, I forget which) introduced a whole lot of new and even more powerful glyphs. In fact, most good glyphs were added then. The catch is that you can only learn them from Books of Glyph Mastery which randomly drop from Northrend mobs. Do you think you can easily farm these books in sufficient quantities to learn all the glyphs? Wrong. In all my Northrend "career", meaning that I've leveled 4 characters to 80, I've only had 2 books drop. The drop rate is abysmal.
This leaves you with only one option, really. The Auction House. Things are much better these days. After these books were first introduced, they would sell for upwards of 1000 gold. During that patch I made some serious gold selling glyphs for dual-specs but my biggest stroke of luck was that I had a book drop for me right when new glyphs were in the highest demand. While you can still get lackluster glyphs from the book, I was once again lucky to get a good one: Glyph of Haunt. During those hectic days I sold a whole bunch of these glyphs at 300 gold a piece and I was the only one who had that glyph on my server. Good ol' days!
But I digress. There are roughly 60 glyphs that can be learned from Books of Glyph Mastery. On my server these books go for 30 gold on average although if you watch out for them constantly you will be able to buy them cheaper than that. 30 x 60 = 1800 gold. That's the investment you're looking at if you want to learn all the book glyphs. And trust me, if you want to be a master, those glyphs are some of the most important.
Finally you're a master but also a few thousand gold poorer (depending on how well you planned your leveling). From here there are 2 major paths: either craft glyphs for yourself, your buddies and your guildies or recuperate your investment and make some serious profits by putting your wares on the AH.
It's easier said than done, especially if you don't have much experience with selling tactics. Inscription is unlike other professions, in that it can cost you close to zero to craft a glyph. To figure out how that works is like some sort of crafting Nirvana (it sure was for me) but it is not the scope of this article although I have explained it to some extent in the post that I just linked.
Inscription remains a very lucrative business but the days of easy profits are long gone, thanks in part to MMO Champion's infamous article. These days you really gotta hustle in order to make a buck. Selling strategies must adapt to various factors such as number and persistence of competition, your own finances, your stock of inks, your source of inks, the price of herbs and so on. Once again, these factors are not in the scope of this article. There's simply too much to discuss and others have dissected this a lot better than I ever could.
After reading all this (are you still with me?) you will probably imagine that I'm trying to dissuade you from becoming a Master Scribe perhaps in the hopes of reducing my competition. Not at all, let me assure you. I'm just trying to say this: get Inscription if you really feel drawn to it. It's a nice and very useful profession. If you have more than one character on a server it will come in very handy. The shoulder enchants are very nice. The offhand items likewise. There are some serious profits to be made with Darkmoon cards (although this might change with patch 3.3). In regards to glyphs, however, it's a whole new ballgame. You will require a lot of time and gold to get all the good ones and even then it is not guaranteed that you will survive the competition.
Personally I have learned almost all the existing glyphs, over 95%. Why not all? Because some of the trainer-taught ones are either useless or won't sell for anything. The market these days is shark-eat-shark. Very hectic. Constant undercutting, which drives the prices down. Barely a month or two ago some glyphs were going for 50-60 gold or more. These days it's hard to sell anything for much over 20 gold. But hey, that's all good! Supply has finally met demand. Profits are lower but since the cost of producing glyphs is very low, they are still solid. Buyers get what they want from a variety of competing sources while sellers... well, some of them have given up while others are doggedly soldiering on.
Think about all the above if you are thinking to learn Inscription for the purpose of making thousands of gold. If you think you are dedicated enough, have enough time and plenty of gold to invest in it, by all means go for it. Otherwise, Inscription remains a very useful profession and is still worth pursuing, even at a slower pace, because WoW has a ways to go and there are more expansions on the horizon.
Patch 1.0.5 commentary
1 year ago