What I would like to know about Trust Levels.

[Gower]

You should be able to find the answers here:

User Trust Levels

You may have noticed that all forum users have a Trust Level, with badges and associated titles. So, what is the purpose of these trust levels, and why do they exist? How do you get to higher trust levels, and what do they do? First, trust levels help us keep the forum safe and clean, by making sure that new users can’t cause too much harm to the community, (accidentally or intentionally) by limiting what they can do. Second, trust levels help us find dedicated, enthusiastic members of the co…

The “Regular” Trust Level is the only one that can be lost if the user does not maintain regular forum using. (and then regained again, of course.)