Question about chat bans

How does the chat ban system work ? I understand you can get 10 or so before a permanent ban. If you get a few over a long period of time (2 years or more) do you still get the permanent ban or do you have to be a repeated offender in a relatively short period of time ? And let’s say you get a single ban and go a long period without issue would you get a warning or just a straight ban for an offense ?