Back in the days when cartridges used batteries to store save data, your precious save files would only remain in existence as long as the battery itself had juice - when the power ran out, the data was lost forever.
Collectors of retro games will know this fact all too well; many RPGs from the '80s and '90s are now practically unplayable as it's impossible to save your game (unless you're willing to crack open the cart and replace the battery, of course).
For one Super Famicom fanatic, the thought of losing his save file for Umihara Kawase was simply too terrifying to comprehend, so he decided to keep his console switched on for 20 years in order to preserve it.
"Incidentally, I'm pretty sure my first generation Umihara Kawase, which has been on in the SNES for over 20 years, has been in operation for over 180,000 hours. If the power is turned off, I'll lose all my replay data. Probably."
The game - which has recently received a sequel on the 3DS - launched in Japan in 1994. Twitter user Wanikun's console has been turned on constantly almost since launch, with one exception - it had to be unplugged for a house move, but amazingly the battery still had enough juice to keep the save file intact. So while it technically wasn't a full 20 years, we're going to let it slide.