Syncthing has re-framed how I think about the file systems of my computers. I used to occasionally plug in my phone to sync pictures and documents to my desktop. Now I don't even think about the distinction between them - the files simply exist on all of my computing devices, and any changes I make automatically propagate to the other devices.

I normally do all my work on my laptop, but I went ahead and set up sync between my work folders and my personal desktop. Syncing ~1tb of work data has been no problem.

I turn off my computers when I'm not home, and my phone runs syncthing-fork on a limited schedule, so I did at one point have some issues with stuff not syncing because devices weren't turned on. So I set up syncthing on a raspberry pi with a big external hard drive plugged in, and it sits next to the router just quietly synchronizing everything in the background.

It's all very set-it-and-forget-it. Just a great piece of software.