How good is your relationship with MIL? I would diplomatically approach MIL and ask her opinion on how reliable the machine is, and adding to it or buying an extra one as back - up. I am sure if you approached it openly that no - one would think you were into'one - upmanship' or competing with her. A new sewer needs encouragement rather than frustration with her/his tools. See if you can talk to them both at the same time to judge their feelings accurately.