Customer entering a new phase

hello :) we have categorized our customers into different lifecycle phases so that we can better approach them. you can see how we have categorized the 4 different types "new acquisition", "purchase", "retain" and "winback" from the formula below. Now i would like to find out when a customer is about to enter the next phase. Would you have any idea how to do that? 

Thank you :)

#Sales Cloud #Service Cloud #Marketing Cloud #Analytics #Trailhead #Automation 

IF( ISNULL(LastOrder__r.EndDate),
	'New Acquisition',
	IF( LastOrder__r.EndDate >= TODAY (),
		IF ( NrOfOpportunitiesWon__c > 1 , 'Purchase', 'New Acquisition'),
		IF ( LastOrder__r.EndDate >= ADDMONTHS(TODAY(),-3),
			'Retain',
			IF( LastOrder__r.EndDate >= ADDMONTHS(TODAY(),-12) ,
			'Win Back',
			'New Acquisition' )
			)
		)
	)