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!
If you are already retired or partially retired when you take the Pledge (which we roughly define as having started to draw a pension), taking the pledge is a commitment to donate at least 10% of your spending money. We define spending money as money received for the purpose of spending on items such as food, rent, travel, or personal items.