Correct!   DO NOT take your file  back to work! 

Sorry, but this is the big issue with A) Working Remotely -or- B) Taking the File Home as discussed above.

In your case, with someone else working on the fie, you CANNOT take the file home.  You would need to set up a Remote Desktop to your machine at work so you can log in and both of you can be working on the SAME file.  There is no way to "merge" the work you did with the work the person in the office has done.  (This assumes the person at work is not using the same machine and you have a multi user license.)

If you're the only one working with the QBs file, then just taking the file home is a great option - assuming you remember to take it both ways all the time.  It gives you a great off-site backup in case something happens at the office (computer stolen, fire, flood, etc.)