This is a very common misconception about DEVONthink. You shouldn’t think about “mastering” DEVONthink. I have been using it for 4 years - easily over 10,000 hours with it - and it still continues to surprise and amaze me! You should think about learning to use it in the way you need to use it. This is most often a much quicker “training period”. Other things you can learn along the way.