What kind of limit is there on task nesting?
From Planfix
In Planfix, there is no limitation on task nesting. You can create any number of tasks that are nested one within another. However, it's worth noting that having too many levels of task nesting could make displaying tasks in lists difficult — you may end up only being able to see part of the names of the nested tasks.
When building our interfaces, we took into consideration 2-3 levels of nesting, which is what is used most often.