If you're like me, you may be the familial expert with technology, and be the one setting devices and services up for other family members.
Recently, I finally bumped up against my 200GB iCloud sharing plan. Not wanting to pay for 2TB when I'm barely going to push 200 GB, I looked to join the family sharing account I had set up for my parents and siblings. However, because of how the accounts are set up, I was worried that my app purchasing habits [compared to theirs] would cause issues with the "Primary Payment Method".
If you join as a family member of a Family Sharing account, usually all purchases go through the primary member. This honestly is great for a family with kids, but falls down when there are a bunch of adults taking advantage of shared iCloud Storage or Apple Music.
Thanks to the Apple Support Twitter account, and my habit of buying iTunes gift cards on sales, I found an interesting way to join a family sharing account, but allow say, a particular family member, maintain their different spending habits. Especially if you're like me and tend to buy a lot more apps/music/subscriptions than your family members.
The solution? To allow charges to go directly to your account first, maintain an "Apple ID balance" on your account. By using iTunes gift cards, or just reloading your account through the App Store Account page, you can load money on your personal Apple ID to pay for your subscriptions and purchases. Your Apple ID will always default to this balance before charging the primary family member's account.
I've just started using this, and it'll be interesting to see how receipts work, but I'm glad that I can join a family sharing account, and enjoy the benefits of shared media/purchases, but without having to worry about trying to balance any payments made by the primary account holder.