The harder you apply yourself, the luckier you get.
Diligence is not merely its own reward. Maybe, if you are of obsessive-compulsive nature, that IS a major objective, but in the course of scrutinizing everything, a good many details that may have been glossed over emerge, and it is in the details that ultimate success is found.
That is what makes great police detectives. And sometimes, crimes of long standing are resolved and finally brought to justice.