Because The Pledge is "for the rest of my life or until the day I retire", if you pledge during your career and then retire, we will continue to consider you a member after retirement even if you are no longer donating. Of course you are welcome to continue donating if you wish!
People who have retired or partially retired (which we roughly define as having started to draw a pension) can join Giving What We Can and remain members for as long as they continue to donate at least 10% of their spending money.
We define spending money as money received for the purpose of spending on items such as food, rent, travel, or personal items.