[wristmittens]

A lot of the replies either rely on third party services (albeit encrypted) or forget about the third part of the holy backup trinity of having something offsite.

It sounds like you're thinking of local backup while you're traveling, which is great. The portability of USB sticks seems perfect for your use case, although I think a 1TB stick is still a stretch, maybe look into a small self-powered external SSD drive. If using OSX you can encrypt it and use Time Machine to auto-backup when plugged in (easy) or just use an rsync script (manual).

But don't forget to ship these backups offsite once you're home. If you get a couple of 2TB drives to account for growth, you could get into the habit of depositing the current backup into offsite location, grabbing the old backup from offsite, and just rotating every couple of weeks. Offsite could be a local bank safe deposit, a work office, or out of town family. (I consider family second-party, not third-party.) Local backup means nothing if you have to evacuate due to flood (east coast hurricanes), fire (california wildfires), or any unforeseen disaster.

I use this method to backup 10TB of photography that I can't do online without a fiber uplink. Thankfully 10TB platter drives are possible these days for me to flat-rate mail to my parents across the country. (And yes, Synology for local backup, that seems to be the hit here.)

[sbjs]

The common wisdom always says have an off-site backup. But what if the backup is small enough to fit in your pocket? I always have a Swiss Army knife on me anyway so if I have a backup thumb drive that’s the same size, it should fit just fine, and be as safe as my house keys. I really think we’re in a new age of self sufficiency because of advances in technology and physical storage size.

[wristmittens]

One of the biggest benefits of off-site backup is stability. That's why something like a bank's safe-deposit box or my parent's firesafe are my preferred locations. A backup in your pocket is great until you lose your keys, your pants get a hole in the pocket, you get pushed into a pond, etc.

[sbjs]

The rsync solution doesn't have to be manual. On Mac you can install a launchd script to run using StartOnMount.