Skill magazines temporarily raise the corresponding skill by ten points (twenty with Comprehension), but wear off after a minute (three with Retention). True Police Stories is the only exception to this general rule, raising the "skill" (critical chance) by five points (ten with Comprehension). There are a total of 213 skill magazines placed in permanent locations; however, certain merchants sell them, providing a limitless source. Also, the magazine vending machines on the Strip provide you with random magazines the first time you open them. Similar to chems, the effects of skill magazines do not stack; using two copies of Meeting People will only provide the bonus of one copy, wasting the second one.