Yes - the best thing you can do - is right click on your app and download the .qvf file to your local system for safe keeping. I am also aware that backups are made on QSCB as well. However they are controlled by the host administrators and can be restored in an event that requires it.
When applicable please mark the appropriate replies as CORRECT. This will help community members and Qlik Employees know which discussions have already been addressed and have a possible known solution. Please mark threads as HELPFUL if the provided solution is helpful to the problem, but does not necessarily solve the indicated problem. You can mark multiple threads as HELPFUL if you feel additional info is useful to others.