This is a well known feature in the SaaS billing world - most large gateways and billing systems (think Stripe, Recurly, Zorua, etc...) have supported this for

This is a well known feature in the SaaS billing world - most large gateways and billing systems (think Stripe, Recurly, Zorua, etc...) have supported this for years. In a recurring revenue model MOST clients are paying via credit card and even when you are a small company, credit cards expiring creates a significant challenge. The auto updating of cards at the gateway / payment processor level help mitigate the impact.