What I backup: Three machines currently, my laptop, my desktop, and my wife's laptop. I don't do a full drive backup as I have no problem re-installing software, losing settings, etc. I just backup documents and media for the most part. This includes wedding photos, rental agreements, bank statements, my own git repos, etc.
All of the photos and most documents also sit in a dropbox folder and are downloaded across all 3 machines. We don't do every photo from our phones because we take a lot of rubbish but usually pull over holiday snaps etc pretty quickly.
When I backup: Each machine has a daily backup using Arq which goes up to AWS S3. I then have weekly backups to Backblaze B2. Only reason to not have daily going to B2 is just to keep costs low. This backup frequency feels comfortable for our uses and we feel fairly comfortable with photos being on dropbox and synced in real-time as those are the most important to us.
I also have a separate backup from my wife's computer which runs hourly and just stores documents related to her studying to minimise loss of work if the laptop crashed during the day.
All in all this costs about $3-$5 a month on AWS and a bit less for Backblaze B2. We then pay for dropbox individual plus at £95 a year. All the backups are compressed and encrypted by Arq and it rolls up and ages off backups for us as I don't really care too much about recovering something from several years ago. Looking at the S3 dashboard we're storing 168.3 GB in total across 4 buckets.
I'm sure many people will say this is insanely little data to backup, but it's not important to us to backup everything really, we'd rather have a simple and cheap system to backup the data that's important to us. With the prices I'd have no problem expanding it to more data if needed though.
In the future I'll probably look at buying a NAS and hooking it up to Arq as well, but that'll have to wait until we've bought our first house.
Final note of praise for Arq, UI is really simple (my wife who's not a techie understands it), you can setup email alerts, and recover individual documents from specific backups without needing to restore everything.
