I am learning more and more that my mother was right about a lot of things but particularly about timing. A superb golfer in her day (she was a single digit handicap at her peak) she taught me that properly timing the start of the downswing was critical to both accuracy and distance. And in love, she always told me that timing was critical when it came to marriage, i.e, whether my future wife and I would be "ready" when we first meet. She was absolutely right!
Timing is also critical in proving an employer's illegal motive for firing, demotions, punitive transfers, etc.. For example, when an employee reports, objects to or refuses to participate in illegal conduct, the timing of an employer's retaliatory action such as a firing, demotion or harassment designed to motivate the employee to quit may be a decisive factor. Does the firing take place within hours, days or weeks of the whistleblowing activity? Whatever excuse the employer uses to justify the firing, demotion, etc. of the whistleblowing employee, the timing of the decision can't be hidden or successfully lied about because it will always be discovered. Timing can also be critical to proving discriminatory motive when an employee is selected for a layoff. An older employee who is receiving good perfomance reviews up to the time when the layoff is being processed and then all of sudden that employee's next review takes a nose dive which is used a a factor to select that employee for layoff may be powerful circumstantial evidence of age discrimination. (Of course, there are other factors to consider in addition to timing such as the performance reviews of of younger peers). Or if your boss suddently starts to be critical of you for no good reason, the timing of that conduct could be indicative (but not necessarily) of a discriminatory motive.
So if you are encountering a workplace situation that feels or seems to be discriminatory or retaliatory and you are concerned that it is your word against your employer's, think about the timing of events that led to your situation. Proving illegal discrimination and/or retaliation is entirely possible even if there is no smoking gun if the timing of the employer's action is suspicious.