Tools, techniques, and strategies for dealing with "the unknown" are a fundamental part of intelligence. As a corralary, the denial of uncertainty is the most un-intelligent of strategies.
It follows that your statement has within it a bit of insight: just knowing that risk matters. So even if you can't know (with precision) your exact 'luck' at every moment, you can build upon the fact that X,Y,Z observed variable could have gone another way had P, Q, R not happened by chance. Just being aware of the magnitude of the potential variation is a useful piece of information. For example, this can guide you to more rationally hedge your bets. Or to "make luck" by managing variables to not happen by chance. Or to just know when it makes sense to keep rolling the dice -- persistence & resiliency. Etc. In this sense, Jessica did touch on something that seems to come in handy here -- resourcefullness -- just in general but in particular when the "enexpected" happens.
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[1] http://www.paulgraham.com/mit.html; see also
[2] http://en.wikipedia.org/wiki/Luck
http://en.wikipedia.org/wiki/Knightian_uncertainty