It goes like this...
The "Doctrine of Love or Money" is based on a simple premise: Your time is valuable. In order to accept a job, you must either really love the people, really believe in the project at hand, or be appropriately compensated. Preferably all of the above.
Any freelance gig must be worth one's time if they are to accept it. Compensation is most often financial, but might also be learning new skills and/or something with a high probability of leading to a higher goal. (Be very careful of any offer of "great exposure" in lieu of other compensation. If the project is so high profile that that's an offer they can make, either you will have already heard of it independently and/or they can afford to pay you.) It is fine to do things to gain experience, but if it is just about experience, that experience had better be worthwhile. If you are being compensated too far below what you think is fair, you will resent the time spent more than you would if you were doing it pro bono.
If you adopt this sort of doctrine, it means that you are only doing the work that you want to do. And you are far less likely to burn yourself out, or to miss the chance to take part in positive experiences because you are caught in draining ones.
Those of us who work in small theatre do it for the love. Make sure the love is there when you take on a gig. If you are asking people to work for love, treat both them and the work you are doing with enough respect and professionalism that the experience is worth everyone's time. I work in a wide spectrum of venues. The places where I work for love have as high a professional standard as those where I work for money. When I am asking people to work for love, they are at the top of the list of those who I recommend and/or hire when there is material compensation involved and they are qualified.
This applies to anything really, but those who work in the arts need to hear it far more than say, aerospace engineers.
A (slightly modified) version of this post was published on Thought Catalog on August 20, 2013.