If Joelle doesn't save her work frequently then if there is a power outage or something goes wrong with the computer then she loses all her work.
To prevent this from happening Joelle should put auto-save on so even if she forgets to save it won't be a problem because it would save for her and she can remain on where she was rather than starting all over. She could also save documents to icloud or save it in her files just in case. She could also make a copy of her work on a different document so if one is wiped out then she can always continue on the other one.
Hope this helps! :3