Deciding whether to go with a particular open source product is an exercise in risk management: understanding the risks of one's possible actions and choices, calculating when a certain level of risk is appropriate to reach a desired outcome, and planning for how to handle negative outcomes. To be sure, opting to go with a particular proprietary product is similar, but evaluating the risk level of an open source product is new terrain for many in the library world and deserves special attention. There are some aspects of evaluation that really aren't much different for open source than for any other software (what features the software offers and if they meet one's identified needs, how well they work, how satisfied existing customers are, what the technical requirements for running the software are, and so on). But some issues need to be approached differently for open source. One issue of overriding concern among most librarians is support. This article takes a critical look at common support scenarios for open source software.