That being said, sometimes a good abstraction can really simplify a complex problem by dividing it up to a set of smaller sub-problems. In such cases, the abstraction is worth it even if there is no reuse. As always, rules like this have to be interpreted in a context.

Also don't forget that code (including the complexity you want to add to it) will probably have only something like an aggragate ~1/3 chance of still being used in a production scenario 5 years or so away anyway (for any number of reason, product change, feature removal, company bought / sold, the list goes on and on...) of course these numbers are anedotal but the point is it can be detrimental to think your code will run as is for the next million years, especially after the first draft