Ask HN: How do you back up your Android phone?

I am primarily concerned with app data. I have many apps like messaging apps that have important private data such as contacts and message history that is difficult or impossible to export. A big concern is if I lose my phone, there are some accounts that can only be recovered using the same phone number, which may be impossible if the phone company refuses to issue another SIM card with the same number (a problem when traveling abroad).

So what do you guys do to get full (preferably offline) backups now that Android 12 has removed backup functionality from adb? Is the only option to use a phone that can be rooted? (unfortunately not possible with my Samsung Fold 3 without disabling the camera).

Slowly, and with great difficulty and unreliability.

Cheers for this, whomever at Google thought it was a good idea to block this without providing equivalent functionality.

For those who haven't encountered it yet, titanium backup (per-app) and TWRP (full partitions) are the gold standard... Assuming you control your phone. I'm not aware of any solution if you don't have root or an unlocked bootloader; AFAIK Google's official solution is sync to Drive (or ... Google One, now? If that's different?), but last I checked support was spotty, and of course that requires internet.

I'm lazy, I set up Syncthing folders for everything and it procedurally backs up those folders as I add stuff to it.

I only backup unique data. Upload all files I want to keep to Google Drive via the app. I have a home Synology NAS with RAID 1 that automatically pulls these files down using CloudSync. Photos are auto synced with Google Photos and I periodically run Takeout to preserve these as well. If I think of it and care, I'll pull SMS messages with SMS Backup and throw those on the Synology.