Explanatory essay about Wikipedia:What Wikipedia is not
This page in a nutshell: The editors on Wikipedia are mainly volunteers. Editors can contribute as much as they want, and for however long they desire.
Wikipedia is a volunteer service. But what exactly does this mean?
Almost all contributions are made in the free time of their contributors.
There are no set crews or teams working on articles on any topic, just those who come along and volunteer information at any time they wish.
You are never required to take any action or post any edit that you personally disagree with. Even if there is a clear consensus against your view, the most you can be required to do is to let others take the actions that they support.
Anyone can take a break for any period of time or drop out whenever they like.
You can always stop working on one group of articles, take up working on another for a while, then resume the previous one, with no expectations from others.
You have the right to quit and never return, and in most cases to vanish—no questions asked, no explanation needed.
There is no minimum or maximum anyone can contribute.