I have data that describes the duration of how long a person views a webpage. This is quite varied and in the context wherein I gathered the data, it was very skewed. People mostly spent short amounts of time in a webpage but sometimes spent a significant amount of time viewing it. I want to discretize the durations (in seconds) into short, medium and long but I don't know how I should do this if the data is skewed.
Initially, I just used tertiles but it seemed kind of off. Tertiles assume equal membership but I'm not sure if this is right because of the skew. Any ideas on a better way of discretizing the values?
EDIT: The reason why I wish to categorize the data is because I want to use it for reinforcement learning. Using the numerical values can increase the search space, so I thought of categorizing the values.