Steve Jones shares a few stories:
Most of the time that I have had to consider risk and reward in the past relates to the effort to fix a problem. Not necessarily the time, or data loss, because those are factors that are secondary to me to the ability to get a fix in. Time can matter, but if the organization has a tolerance for time, then I can work with that.
This also goes to whether the organization is willing or likely to try to fix things, or even if they are willing to let me fix things. If not, then I am way more careful about how to approach a design decision.
Click through for those stories.