Hi there.
So the way I understand it if I dump engineering I will lose all the old recipes and would have to relevel them BUT i could by tomes for the last two expansions to get the old recipes back but still need to level?
I would also lose my vanilla status so I would have to farm up that in order to qualify for the darkmoon faire profession quests again?
I wish they would just snapshot it but oh well let me know if I am on the right page…
The tomes teach recipes learned via questing for that particular expansion. They will not teach anything for prior expansions. You will also need to level the professions again in order to get any use from anything that requires higher expansion numbers. Engineering, in particular, has a bunch of this. Some major ones: Jeeves (Northrend 75), MOLL-E (Northrend 50), Goblin Glider tinker (Pandaria 25 to learn), and so on. Finally, at a minimum, you can’t get the Zapthrottle Mote Extractor recipe again as the quest is not repeatable.
Right thanks. There is no tome for all the expansions ?
Nope. Legion has tomes for all the professions. BfA only has tomes for gathering professions from what I have seen.
… and the tomes only teach those recipes you got from non-repeatable quests.
Thanks everyone not going to dump it then 
With the whole Profession revamp to where they go by expansion. I’d love to see them come out with Tomes for each expansion. I would expect all the system needs to see if we had a Pattern that may or may not be in game any more is for us to log onto the toon and open the profession book for all the profession patterns weve learned.
They could even make these tomes craftable.
True for me the thing is if i dump engineering it can be a pain to have to level up multiple expansions to get my glider and rocket boots back…
I have always felt sory for those with those unobtanable patterns. who dont want to drop that profession due to the fact the pattern is no longer obtainable. If blizz did do a Tome for each expansion least then those people wouldnt have to worry if those tomes brought back those patterns as well.
I think one of the issues with making a tome available for each expansion is that people would switch professions like they switch specs and I think Blizz has consistently considered professions as being something you commit to long term.
Each expansion seems to have it’s professions du jour. I don’t think everything in the game should have some instant gratification mechanism.
Would agree but the game has changed, and so do the professions on how they work, etc. Now it’s a completely different ballgame on how to level stuff. Before there was a way to do it and it was standard really now you have to do it across multiple expansions…
Good points though…