Evaluating intelligence increases the damage and potency of magery, but only the damage of direct damage spells such as flamestrike, energy bolt, meteor swarm, etc. It has no effect on spells such as greater heal, nor will it make summoning spells (such the summon elemental, or summon daemon spells) last longer, or a make a spell such as wall of stone last longer, etc. Also it allows to evaulate the intelligence of any creature.
Skill Response to INT Conversion
Skill Response Target's INT "It looks smarter than a rock, but dumber than a piece of wood" - * "Slightly less intelligent than a rock." 1-9 "Fairly Stupid." 10-19 "Not the brightest." 20-29 "About Average." 30-39 "Moderately intelligent." 40-49 "Very intelligent." 50-59 "Extremely intelligent." 60-69 "Extraordinarily intelligent." 70-79 "Like a formidable intellect, well beyond even the extraordinary." 80-89 "Like a definite genius." 90-99 "Superhumanly intelligent in a manner you cannot comprehend." 100+
From an Evaluating Intelligence skill level of 76 you will also see the mana level of the target displayed as a percentage of it's maximum level, for example "This being is at 100% mental strength".
* Non-living objects (obviously) fall into the category of having no Intelligence.
Download and install Razor.
Record a macro that looks like the following:
Use Skill: Evaluating Intelligence Wait For Target Last Target (an NPC) Pause 10000 Say: Guards
Next ALT+Click on the NPC to Auto-follow them, or alternatively find a stationary NPC like Lord British. Lord British is an exceptionally good choice because he can't be killed or lured away while you're AFK. This will Grandmaster your skill after some time.