I've noticed that the consumption of caffeine increases my productivity and improves my mood. That being said, I'm wary of acquiring a tolerance - I would like to take a low enough dose infrequently enough that I have an increase in energy and mood when using it, and return to my baseline when not using it. I would like to avoid developing a tolerance to the point that consuming Caffeine simply brings me back to what was previously my 'baseline'. I've done a fair amount of searching online, and was unable to find any reputable sources detailing information on caffeine tolerance.
On average, how much caffeine will a person have to consume, and how often, to develop a tolerance?