Luck is the irreducible chanciness of life. Luck cannot be controlled, but it can be managed.
What do I mean by luck versus risk? Risk is the interaction of the uncertainty of future outcomes with the benefits and costs of those outcomes. Risk can be studied and modified. Luck is the irreducible chanciness of life—chanciness that remains even after learning all one can about possible future outcomes, understanding how current conditions and exposures are likely to alter future outcomes, and adjusting current conditions and behavior to optimally control costs and benefits. Some things are determined by luck, and it is a fool's errand to try to totally control luck.
The philosopher Rescher (2001) states it well:
The rational domestication of luck is a desideratum that we can achieve to only a very limited extent. In this respect, the seventeenth-century philosophers of chance were distinctly overoptimistic. For while probability theory is a good guide in matters of gambling, with its predesignated formal structures, it is of limited usefulness as a guide among the greater fluidities of life. The analogy of life with games of chance has its limits, since we do not and cannot effectively play life by fixed rules, a fact that sharply restricts the extent to which we can render luck amenable to rational principles of measurement and calculation. (pp. 138–139)
Rescher's point is that luck is to be managed, not controlled. The question is not whether to take risks—that is inevitable ...