I agree with what's been said here, especially with what Leo has to say about being strategic. From his "How to be a Strategic MotherFucker" video, what we do today should be informed by where we want to be in x amount of years, months, and weeks. This boils down your question to "what can I do today to get me where I want to be in the future?" There's really no point in allocating your energy and resources on activities you don't plan to master.
With that being said, trying to accomplish too much may possibly cause you to burnout. In my experience, after going through a stage of serious work output, I fatigue and lose motivation in accomplishing my goals. This can lead me to stagnate for a certain amount of time which could have been avoided by being more conscious of how much I'm working.