The ebb and flow of guild drama can vary widely based on the player base of the guild, but, in my experience, a 3-4 month cycle would seem fitting, because of the world in which we live. For instance, the most common reasons that I have seen people leave the game have to do with a small handful of things, such as:
- Another game
- Family commitments
If you were to look at each of those, they also tend to have similar cycles:
Most businesses, especially large ones, operate on a quarterly cycle, which generally means that workload picks up near the end of each cycle. Because the workload picks up, it means that their employees will be more stressed, with them trying to find more time in their day to complete their assigned tasks, generally leading to people cutting out their leisure activities, thus leaving the game.
Because games are created by businesses (who most likely operate on a quarterly cycle as previously mentioned), those games tend to come out either at the very start or very end of a quarterly cycle. This means that people that are getting bored with the game would likely switch to a different game at about a quarterly basis.
Most school systems are set up with a calendar year based on trimesters, with 1 trimester of vacation and 2 trimesters of learning. Many parents will limit play-time of their children if they do poorly in school, so it would be common to lose younger players around those times. Additionally, because most schools do have a vacation period, it would lead many players to drop when returning to school.
That is not to mention the players that are attending college, where certain classes, or periods during classes, require more dedication than others (finals week), you will undoubtedly lose players around those times as well.
Family commitments vary widely based on a variety of things. If the family is just starting out, you could expect people to leave due to having children, which thankfully allows for some advanced notice. However, if the family has children that are a bit older, and participate in sports or other activities, those things tend to follow closely with the schedules of schools and seasons.
Because all of these situations can compound themselves, and happen all at the same time, it would seem logical for there to be a 3-4 month cycle where people are playing/leaving the game.