Although, when I was growing up the freezer was defrosted approximately once a year and/or when everything was covered in ice - untill I was old enough then it became one of my chores . . . NOT FUN ! ! !
However, since then all my refridgerators were self-defrosting . . . But since getting the mini-freezer I did some research . . . It is "My" understanding:
"To maintain the efficiency of a manual-defrost freezer, it should be defrosted each time it develops a quarter-inch of ice build-up on the interior walls. Many people defrost their freezers once a year, but you may find that you need to do yours more or less often depending on your usage habits."
"My" mini-freezer has been plugged in and running since December 2019. As you will see in the photo I post earlier, it is not "packed". Just checked it and there is barely a coating of frost on the inside walls/top/floor of the freezer so far.
Given that - guess by the end of the year or begining of next it will be time . . . We'll see . . .
.
I didn't get a plastic scraper - NOT FAIR ! ! ! 
