Intelligence Damage and Skill Points

[An Enemy Spy]

One of my players just made it to level 5 but has taken a bit of Intelligence damage that reduced his modifier from 1 to 0. When determining his new skill points, does he use the new modifier or act as if the old modifier is still in effect since the ability damage is temporary?

[daremetoidareyo]

Use their normal intelligence modifier because it's a temporary problem.

Leveling up shouldn't be thought of like an instantaneous increase. Doing so invites all sorts of munchkinry. ie. "If I have this spell active as I pass the 8,000xp threshhold, I can get early qualification for a prestige class!" That sort of stuff is silly. XP and leveling up represents long term increases in capability, luck, and plot importance.

[xXAmaroqXx]

Im not sure but it looks like you didn't determine which Rule system you use exactly.

At least in Pathfinder, which is mostly based on 3.5, the rules for ability score damage are as follows:

Temporary Bonuses: Temporary increases to your Intelligence score give you a bonus on Intelligence-based skill checks. This bonus also applies to any spell DCs based on Intelligence.

Permanent Bonuses: Ability bonuses with a duration greater than 1 day actually increase the relevant ability score after 24 hours. Modify all skills and statistics as appropriate. This might cause you to gain skill points, hit points, and other bonuses. These bonuses should be noted separately in case they are removed.

Ability Damage: Damage to your Intelligence score causes you to take penalties on Intelligence-based skill checks. The Ability Damage penalty also applies to any spell DCs based on Intelligence. See Ability Score Damage below.

Since Ability damage uses the same rules as the temporary bonus rules, AND since ability damage usually is temporary, it does not lower your skills in any way, neither at the point of receiving them nor at the point of getting them. Since this ruling makes sense, i would apply it to any rule system you're using. If your Intelligence is permanently raised, such as via a circlet of incredible intelligence, you must actually select skills to dedicate the additional skill ranks to, in order to prevent people from using it to redistribute their skill points.

In other words, you use your base intelligence modifier when levelling up, and modify your intelligence (and possibly skills) going from there.

[Zanos]

3.5 does not differentiate between 'permanent' and 'temporary' ability scores. While certain items and effects such as fox's cunning and headbands of intellect specify that you get no additional skill ranks, there is no general that 'temporary' changes to intelligence don't affect skill point gain on level up.

RAW, you would use the reduced score. Conversely, if you find a source of bonus to intelligence that isn't an effect that explicitly lists it does not grant skill points, you will gain more if you level up under its effects.

[weckar]

RAW, you would use the reduced score. Conversely, if you find a source of bonus to intelligence that isn't an effect that explicitly lists it does not grant skill points, you will gain more if you level up under its effects.... But lose them again right when the effect expires. And if that's true, then gaining that buff at any time -- not just during levelup -- should give you skill point, as bonuses are the blind inverse of penalties.

[Zanos]

... But lose them again right when the effect expires. And if that's true, then gaining that buff at any time -- not just during levelup -- should give you skill point, as bonuses are the blind inverse of penalties.
Skill points are not retroactive in 3.5, for better and worse.