Throughout grad school I worked on mostly one project at a time. Of course there were many sub-parts going on simultaneously, back ups etc, but they were all aimed at answering the same question, the basis of my doctoral dissertation. When I started my post doc we outlined two projects A and B. Project A was taking up immediately from where someone had left it, and had an experimental framework outlined. But it required so much groundwork and set up, while project B required so much of my understanding of the literature and conceptualization, that A had been consuming all of my time for the first year. B is supposed to be my "main project", my baby, and it has only taken off in fits and starts whenever I got time from working on A. Finally, A has taken off, and I have attained a degree of confidence and command over it so that I can now work on getting B up and running too. Now I am actually doing what they tell you to do all the time, work on 2 projects at a time. And I am loving it!
A and B are entirely independent of each other. So I go in everyday and open up my black notebook, which I record my experiments and observations on A. Somewhere in the middle of the day I switch off from A almost completely, switch gears and start thinking about B. I open up my blue notebook, design, plan and conduct experiments for B. It's like living two mini-lives in a day! They both employ different techniques and different experimental models, so I am learning a lot of new stuff now and getting to play with very different tools. They are also aimed at answering very different questions, and I am beginning to enjoy juggling between the two disciplines and the mental gymnastics of jumping laterally from one thought process to the other. And there is the thrill and rush having all of these different things to do and stay on top of, which gives me that kick to see me through the long days.
And every once in a while, A provides a vague insight or segue into B or vice-versa, and those are delightful moments, like unexpected bonuses. In the bigger picture, A and B are also after all pieces of the same huge puzzle: understanding how and why cells do what they do.The plan is to make the two roads meet at some point in future, and I am excited to see how and when that intersection happens!