First, realize that ‘‘stay clean’’ time windows are a matter of company
preference and past practice. Progressive discipline shouldn’t be looked at as a ‘‘formality’’ that companies have to go through before they’re free to terminate someone for cause. On the other hand, it would be na?¨ve to think that all situations will improve once managers provide dedicated attention to their underperforming
employees via the progressive discipline process. Therefore, documenting the expected time frames for performance improvement
becomes a critical part of all written warnings.

Be reasonable. Certain consequences should have no time limits. An employee who engages in behavior that could be construed as harassing or discriminating, for example, may not be ready for termination in your opinion. However, you’ll want to send a strong
message that such behavior will not be tolerated in the future and
that any additional incidents could result in termination:

John, if you ever again engage in conduct with a coworker, supervisor, or customer that could be considered hostile, offensive, or antagonistic, you may be immediately discharged.

Mary, if you ever again loudly and publicly reprimand your secretary
or other subordinates, if you use profane language in the workplace,
or if you demonstrate behavior that could be construed as condescending or stripping individuals of their dignity, you will be immediately terminated.

Remember that open-ended consequences typically allow you to retain maximum flexibility. Rather than placing time windows around an employee’s ‘‘stay clean’’ period, simply document the expected consequences this way:

Jim, failure to demonstrate immediate and sustained improvement may result in further disciplinary action up to and including dismissal.

Taken From : The Hiring and Firing Quention and Answer Book