What do you mean with “conclusion”?
Do you mean how long should be each timebox?
Timeboxing is natural life as all of we die… we could not set plans for more than our expected life. If you translate that to single activities, there is a time cost associated with each one. Then before beginning each task you project what you expect to have finished after that time. And if you finish or not you should decide if you should continue investing time on that way or not.
Also, the quality is infinite, then timeboxing help make things happen in a time we consider appropriate to spend on it.