Have had frost free freezers and fridges for the past 15 years. In the UK.
Some years back, my much older brother purchased a small fridge with a very small freezer with a separate door at the top. Not frost free.
He telephoned me to ask advice as he said the freezer was getting iced up. I told him to wrap the small amount of stuff he had in there in newspaper, as the defrosting of a small freeer should take less than an hour. Told him then to place a bowl of boiling water inthat freezer, and that should do it.
He phoned me the following day to say it was not working, and I could not understand why, until I visited him two days later to find a total mess in the kitchen warer everywhere.
I could not understand what was happening, so sent him into another room and I checked and then discovered that he had put those few freeer items Duly wrapped in newspaper) in the fridge section and then turned the dial upto as high it would go. I had ommitted telling him to switch off the whole machine!!!!!
Poor little fridge/freezer - amazed he had not burnt out the motor, he had left it running at it highest whilst continuously putting in those bowls of hot water into the freezer section.
Took me less than ten minuts to sort it all out and note to myself that any instructions should always start with basic one of turning machine off!!!
My first freezer was a very large commercial chest one. Only way of defrosting it was for either myself or hubbie to climb into it (once emptied), in order to be able to mop up all the water defrosting in its base.