I have a "minimum" stack and my "maximum" stack. I'll explain.

The minimum stack is the bare minimum of books I want to complete this year. This is usually around 20 books, esteemed classics or books I'm desperate to read that no matter what, this year, will be read.

The maximum stack is books I'm interested in, happen to own, or are tangentially related to the minimum stack. This usually expands the tbr to around 50. Books come, books go, if I take one off the maximum stack its no big deal. It usually gets replaced in a week by something else that piques my interest.