Duncan, it should take effect immediately. Just make sure you're signed in and click on the head icon to bring up the menu, then my address book. From there you can delete your old address and add your new one. Changes will be automatic. If you have any issue you can contact buds customer service at 859-368-0371 Monday thru Friday 9am to 9pm or you can use the blue chat button at the bottom right corner of your screen. They'll be able to assist you. We're just customers as yourself not buds employees so we can only point you in the right direction. Hope this helps.

Duncan, the change will take effect immediately, as soon as you change it on your account.
Stay safe & have a great day!

Hi Duncan and welcome. Generally within 72 hours. You can see if Buds Customer Service can speed things up at 1-859-368-0371 9am-9pm EST Mon-Fri. or use the Blue Chat now button at the bottom right corner 9am to 9pm Mon - Sat and 9am to 7pm Sunday.