I agree entirely, which is why my writing year is strictly regimented in that respect. Medium is not my primary focus, my novels are, but there are busier times (such as now, when I'm writing the first draft of my latest) and times when I write no fiction at all, giving my brain a break (the whole of December, for instance).

I also have other writing freelance work I don't generally talk about, as it isn't particularly interesting. But it is easy and quick to do, and helps put food on the table.

A good practice for any writer is to stick to office hours whenever possible. Yes, there will be some busy times, when "overtime" is needed, but I would recommend not being an arsehole boss to yourself.