Skill points are earned 1 per level to a maximum of 40. This number can be increased by using trainers, picking up books and by some equipment.
Is it possible to simultaneously max out all the skills in a single play through?
What is the maximum number of skill points that can be achieved (in total) using the trainers?
What trainers exist? What are the restrictions on their use?
What hoops would I have to jump through to get to the theoretical maximum levels?
Are there any items that increase skill points that might affect using the trainers (ie should I hold off on using them until later in the game) or should I plan to Fateweave later on to collect them all?
Best Answer
First of all, yes, your gear can have skill bonuses on it.
Every race gets 4 points worth of skills.
By level 40, you'll have earned 40 skill points from leveling.
The highest tier Might-Finesse-Magic destiny gives you +3 to every skill (for effectively 27 skill points).
A trainer will only train you once, and only if your current skill level falls in the range they can train. However, this isn't a big problem because...
You can use a Fateweaver to reset your skill points. This would allow you to get a skill to whatever range it needs to be to use a given trainer. And for the record, resetting your skill points doesn't blow away any training bumps you've purchased.
So, the points from leveling, race, and destiny give you 71 of the 90 skill points you'd need to max everything out, which leaves 19 skill points you'd have to come up with from trainers.
Ignoring skill bonus gear for the moment, that leaves the question... are there 19 different trainers in the game? Yes, there are. In fact, it looks like there are 4 for each skill.
Trainer Locations
Also, there is one skill book for each skill. Or rather, even if you can find more than one, you can benefit from at most one skill book per skill. There appear to be some fixed locations they can appear in... whether or not they can sometimes appear randomly in other locations seems to be up for debate. Don't worry about reading every single book you find just in case it is a skill book... they're very obviously named as "Skill Book (whatever)". Here is a partial list of their locations... I know for a fact it's incomplete because they only list one Detect Hidden book, but I found at least two while playing:
Book Locations
One other thing I've discovered is that at the lower levels, when skill points are still tight, you can pretty much ignore the crafting skills (Blacksmithing, Alchemy, Sagecraft) until you actually want to craft the higher level items. When you're ready to craft some awesome gear, drop the money at the Fateweaver on a respec, dump your points into the crafting skills, and do all your crafting at once. Make those potions you want. Combine your shards into higher level shards. Crank out your epic gems. Build yourself some fancy swords. Then respec again to move your points back to where they were. Do this at the same time you're respeccing so you can hit the trainers you missed, and you kill two birds with one stone. It's true that you will miss out on better herb & shard drop rates if you ignore Alchemy and Sagecraft during normal adventuring, but I think putting those points in Detect Hidden or Mercantile more than makes up for it. There's only so many shards or potion components that you really need. And with high Mercantile, you've got plenty of gold to buy whatever you'd like.
Lastly, note that the bonuses you get from the Might-Finesse-Magic destinies, skill boosting gear, and skill boosting potions can all raise you beyond your normal maximum for your level, giving you early access to some of the higher level skill features. For instance, you can get the ability to craft epic gems (which requires rank 8 of Sagecraft) prior to level 16, which is when it normally unlocks, by buying it up to level 7 and then using one the above methods to give you a +1. For example, in the screenshot below I've got +1 to all skills due to the Tier 3 Might-Finesse-Magic destiny. You can see my bonus skill points as the dark green shaded boxes.
The important takeaway from this is that so long as you're willing to throw a little gold at the problem (which you're going to need to afford all this training in the first place!), you don't need to stress out about exactly how and when to spend your skill points so that you can maximize trainer usage. The Fateweaver respec lets you get around the problem of trying to fall in the exact range of a skill for a given trainer. Just make a note of trainers you couldn't use, and once the list gets long or you otherwise have a reason to respec, go back and hit them all. If keeping a list is too much work for you, on your World Map, you can also hover over the names of the places you've been to, and it will tell you if there is a trainer there.