Ideally you want to be symptom-free for a good stretch before returning to work. Concussion symptoms can linger, so it's best to do as much recovering as possible before encountering the stresses of the workplace and the hurly-burly of everyday life. Recovery often takes much longer than people initially estimate. Taking it very easy and staying "sub-threshold" of symptoms in the short- and medium-term will pay big dividends in the long term.

IMO, you are *not* doing yourself a service by rushing back as soon as you feel sort-of OK. It's all about striking the right balance. Returning to work is good, but it needs to be sustainable. You should plan on returning only when you're ready to do so, and even then gradually and backing off if you have problems.