ToME: the Tales of Maj'Eyal

Is it ever worth it? Do you use it for some builds? This +0.2 to talent tree looks inferior to new category\rune\infusion

yes its often worth it. If there is a tree that you have 5/5 in every category its like 4 free talent points. I find its useful to increase the mastery of the blood tree on corrupters. Generally late game you use it to augment the tree that you use the most.

Stealth, dual weapons, poison, corona tree, shades, etc. Often the effects are substantial! E.g., an extra shadow for doomed

An extra category is most useful if you have the points to effectively use it. Some classes already have too many places to put points.

I almost always go for increasing my most used category if there is not a good locked category I need. In most cases three runes/infusions is enough for me.

I increase the Focus tree as a mindslayer if I'm planning on using it for primary damage dealing. To my mind, the +10% damage that you get on a normally scaling talent is not worth sacrificing the added versatility of another skill tree, even with 1/1/1/1 investment.

(note: the Focus tree for mindslayers scales damage more quickly with talent level than most others.)

As a general rule, if I'm sinking 5/5 points into every skill in a tree, it deserves a cat point. This is especially the case since the categories that tempt you to put in 5/5 across the board are usually the ones where there are a lot of synergies within the tree - so getting that virtual sixth point in each skill can give you that much more benefit.

What about runes? Is it safe to say that adding a rune is always a waste of a category point?

Not at all. Shield/Shield/Teleport/Controlled Phase Door/Invisibility is a perfectly respectable five rune loadout. And that's assuming strictly runes as opposed to inscriptions in general, in which case you also have heals/regens, wilds, and movement infusions competing for slots.

Inscription slots are essentially the default category point expenditure against which other category point expenditures are measured. Inscription slots by default give you panic buttons, and having more panic buttons is *always* good.