Automation Rules are a powerful tool when combined with your Sales Process. Below are some common scenarios where you can implement Automation Rules.
Lead Status/Score/Owner Changes
For this example, let's say you score your Lead records and you've got multiple Plays created that align appropriate outreach based on the score. (For example you wouldn't send an Auto Email to a HOT Lead, those emails should be customized. And you wouldn't send a InMail to a low touch Lead because those cost money.)
Create a sequence of Automation Rules using the "Add to Play" action and the option to reverse the action if the criteria is no longer true.
This method is great because it solves for any changes to Ownership or Scoring. And as the Rep changes the Status to advance it thru the Sales Funnel there's an Automation Rule & Play to support it.
Remove Dead / Do Not Contact Leads
Now, let's pretend you have a Lead Status of Dead and Reps will specify this Status if they have no means of contacting the record or if the Lead requests that they not be contacted again. Create an Automation Rule looking for Lead Status equals "Dead", and specify the action to Remove from Playbooks.
Then put this Automation Rule at the top so that it will always take precedence over any other Automation Rules that may still qualify.
(Use 'Click & Drag' to re-order your Automation Rules.)