Many things can be re-imagined. For example, we eat meals at certain time, and have implicit rules for what to eat for what meals. As long as it does no annoyance to anyone else, why not have omelets for dinner? Oatmeal for lunch? You can eat one meal a day or five.
You might notice you have little rules for yourself that don't really have any real reason. Why do your socks have to match, for example? Do you always have to take the same route to get the same place? Does a paper you assign for a class have to be a textual analysis, every single time? Do you walk around looking at the ground and avoid eye contact with people you pass by?
Now some of the rules and habits you might want to keep, or at least follow most of the time. There may be negative consequences for not following a rule, or you may have **good reason**, even if it is only that by following a rule you don't have to make up your mind every time anew about some trivial thing. So I say yes to article refereeing and no to book reviews most of the time.
A lot of things, though, are simply arbitrary. You could be preventing yourself from doing something valuable simply because you have a rule that you don't even know that you have. Maybe you don't read outside **your field** because you feel you can't even keep up in your own field. Maybe you define your field arbitrarily: British prose after 1750. Well, what stops you from going before 1750?
I was reading a book recently that claimed that the reasons we give for what we do are arbitrary (bullshit was the term he used.). If someone asks us why we did something, we come up with a reason to satisfy the person, but that reason probably has nothing to do with anything except for being the most satisfying answer in a social situation. We just have to satisfy the question, as a social convention. It's not necessarily false, but most events do not have singular reasons. They are invented after the fact. So if I come five minutes late to class, I can say "Oh, I was answering an email and lost track of the time." But in fact that is not the reason. Since I never do come 5 minutes late to class, if I did it would be because coming to class early was not a priority for me. So my reason is kind of irrelevant. I might as well say I came late because it's not important to me. That's why I tune out when a student says they missed class because of x. All the matters, really, is that they missed class.
**Your field** is kind of a bullshit concept too. I understand that your department hires you with the idea that you will do something relevant to the academic mission of the department, and that they have an interest in you doing more or less what you were hired to do. But there is no reason why you can't shift a bit and have a more expansive view.
When you write a book about an author or a subject, you often are following implicit rules that you haven't even thought about. You could do it in a much different way, but you only see certain paradigms and think those are the only ones. Of course, your unconventional book might be harder to sell, or have other problems, but those aren't very good reasons.