Skill points are earned normally as per the SRD rules with one exception. If a character's Intelligence modifier increases, they retroactively gain a number of skill points equal to 1 per HD. This can only result from inherent bonuses to the Intelligence score. Magic items that increase a character's Intelligence (such as a headband of intellect) do not increase the number of skill points the character has.

For example, Luthien is a level 11 elf wizard with an Intelligence score of 19. At level 12, her Intelligence increases to 20, making her modifier +5. She gains a total of 18 skill points at level 12 (7 for 2+Int mod and 11 bonus for past levels). These retroactive skill points are for the base Intelligence score only, so if Luthien is also wearing a headband of intellect +4, she does not gain additional skill points due to her increased Intelligence modifier.