Thanks
3 answers
I'd say it really depends. Importing on a sandbox might be handy if you want to practice the process before a hard go-live date. It's also handy if the object is very active, and new records are regularly added to it.
If the import is straightforward and undoing any mistakes should be trivial (meaning there isn't further automation on the records that affects other things), then it should be safe. It would be even safer if you use Data Loader, as it creates a result file that gives you all the inserted record IDs. You can use the file to mass-delete in case you want to roll back the import.
But honestly, it's just about how confident you feel with it. If you've never imported data before, then by all means practice on a sandbox.
