If you live in an area with hard water like me, this 4L distiller is a worthwhile investment. I've been using it specifically to create distilled water for washing my hair, and the difference is noticeable! It's incredibly easy to use - I run it overnight and once during the day, producing enough water for both me and my partner (about 2 gallons total). The design is solid and well-made, and it even comes with a couple of replacement filters and a cleaning powder to tackle mineral buildup. Clean it is pretty easy, just give it a quick rinse each time. Every two weeks or if there's excessive buildup, I simply add a bit of the cleaning powder and let it run without the lid. I'm surprised to see reviews complaining about the residue – that's literally the entire point of distillation. Of course you'll have mineral buildup after distilling hard water... Overall, if you're looking to improve your water quality, this distiller is a great choice. Highly recommended!