There are no set rules on how long you can be banned for. A mod can give you a 1 day ban or 100000 day ban if they see fit.
7, 14 and 30 day bans are the most common ones used by global mods and admins. While I usually default to these, whenever there's a situation where an offense just doesn't match the most common severity levels (is lower than the lowest, higher than the highest or in between), I tend to use 3, 5, 10 or 60 days for such offenses.
I understood, but the guide of @hilariousandco should be updated with a few words on what you both disclosed.
Currently, if a newbie visits that thread, they will be misguided somehow. They will think there are only three types of temporary bans, with 7-days, 14-days, and 30-days ban period.
Staff do not want to hand out bans for unconstructive posts but if we feel that you as a user are continually making very poor or unsubstantial posts due to your paid signature the following bans will be issued:
First offence: 7 days
Second offence: 14 days
Third offence: 30 days
Fourth: Permanent ban
I also know there is a rule quoted below, but I still think if that guide updated with some details on ban periods of temporary bans, it is likely better, IMO.
23. When deciding if a user has broken the rules, the staff have the right to follow their interpretation of the rules.[e]