Each infraction comes with a different point value and a different expiration date. Lower level infractions such as those for spam, expire in normally 10 days. That means that after 10 days, the infraction itself stays on your reccord but the points are no longer in effect.
Infraction points are important because active ones stack on eachother and with 3 active infraction points you get a 24h ban. And the more active infraction points, the longer the ban. If you get 10 active infraction points, you're permabanned.
Global Moderators and Admins can also give custom permanent infractions or custom infraction. These carry a custom value chosen by the moderator or admin and custom expiration date that can even be permanent. Its reserved as one of the last disciplinary measures we might use.