How can NPS be configured to go out on a rolling basis?

Within the Powerlist you can set the timeframe you would want this to fire. For us we did it based off of the Renewal Date in SF and have the NPS survey rolling throughout the year. 

We use the Life cycle weeks per year field on the Customer Info object. It keeps track of how many weeks an account has been a customer. The value is increased by one every seven days from the Billing Start Date up to 52 then resets to 1 on the customer's anniversary.

You can add this field as a criteria in your power list and specify how often  you want to send the NPS on (e.g. 3 m13 weeks, 6 m26 weeks, etc.)

We send NPS surveys quarterly, so this was the setup I just mentioned over here :-)

I created a Salesforce Formula Field, Integer, to give me the month of a customer's start date:
MONTH(dateCustomerStart__c)

I then created a Formula Field, Checkbox, to tell me whether I should be sending the survey "this month":
MONTH(TODAY())= Customer_Start_Month__c ||
MONTH(TODAY())+ 3 = Customer_Start_Month__c ||
MONTH(TODAY())+ 6 = Customer_Start_Month__c ||
MONTH(TODAY())+ 9 = Customer_Start_Month__c ||
MONTH(TODAY())- 3 = Customer_Start_Month__c ||
MONTH(TODAY())- 6 = Customer_Start_Month__c ||  
MONTH(TODAY())- 9 = Customer_Start_Month__c

Thanks for the help everyone!

We are looking into reporting at a couple of specific points in the customer lifecycle and waiting a month would miss the mark. 

What Lauren said. :)  You can use a campaign with higher cadence, but a Powerlist which narrows the recipients to just the right audience.

We send out surveys via a few outreaches.  We send monthly to a Powerlist of customers whose accounts are up for renewal in 4 months (with a follow-up a week later to those who didn't open the first email).  We also have an NPS campaign that triggers daily, but the Powerlist only includes customers who just completed onboarding (and the survey is worded with a focus on the onboarding experience).  Another is more of a CSAT survey than NPS, but again, it's sent every day.  The Powerlist includes anyone who had a service desk support case closed the previous day.