Google Ads announced that you can now enable continuous audience sharing in your manager accounts. This allows you to not have to share them manually all the time, instead just enable it and Google will continually share the audience lists across accounts.
Google said "Whether your goal is to increase sales or drive brand awareness, remarketing to people who have already engaged with your website can help you grow your business. With a manager account, you can share audience lists across accounts–but it requires multiple steps to set up. To make it easier to quickly share your audience lists, you can now enable continuous audience sharing in your manager accounts."
Here is a screen shot:
Google added that when you opt in, any remarketing lists you create in your manager account will be shared with all of your existing and future sub-accounts. These accounts can receive lists from multiple manager accounts, and you still have control over which lists are active. In the coming months, you’ll also have the option to share lists created in sub-accounts with your manager account.
Forum discussion at Twitter.