Limitation on the maximum number of project areas, team areas and categories in RTC
One answer
There are no set limits specified for these items, but practical limits exist. There are many installations with hundreds of project areas, and thousands of team areas and categories. We have found that with thousands of team areas there can be database-specific thresholds that when exceeded can cause performance slow downs. Customizations can also introduce performance bottlenecks when many contributors, team areas and categories are used because they can for example trigger iterating through contributors which determine the role by looking up team area and category. A few thousand or so does not seem to cause performance issues; more than that and you may need to tune your database. Performance is a focus item in RTC development and in every release improvements are made, so later releases progressively ease bottlenecks.
Many categories are supported and the limit here is often Usability. If there are too many, users would need to filter to select from a large list. However, there are use cases that justify many categories.
Lawrence Smith [IBM]