covfefee wrote:My pi contains sensitive data that I don't want to lose.
Do you mean "sensitive" as in personal or commercially confidential (and therefore to be protected from unauthorised access), or as in valuable -- you lose time/income if you lose the data?
In either case backups are essential. Match the backup regime to the value of your data. Valuable data deserves at least two offline copies. In many cases one should be in a different location.
How often does your data change? How much harm is done if your backup is a day old, or a week old? If a day/week is acceptable, then follow rpdom's system and make a daily backup.
Then on Friday take the backup home, and on Monday bring the previous backup back.
If you need better security for fast moving data, you need to look at on-line replication to a second system, with no common point of failure.
(It is always possible to find a common point of failure, you just have to make sure that the likelihood of that event is low wenough to be an acceptable risk.)
If the data is personal, you may need to consider where it is stored and making each location secure. Keeping a copy of personal data (or even some commercial data) at home may not be acceptable.
covfefee wrote:What is the risk posed by power outages/storms/etc.?
The power fauilure can lead to a corrupted (and sometimes unrecoverable) SDCard. If that is your concern, a UPS is necessary -- search for "MoPower" for boards which may suit your need.