Michael, my distiller is dentist-grade made in Italy, its being sold in Europe mainly to dentists, I know for sure that similar distillers are available in US.
It needs around 6 hours to process ~ 1 gallon of water. It is very small device, a stainless steel container where the water is heated, on top of it, it has a cover that holds a serpent with a fan, so that the vapors from boiling the water are lead into a collecting container, on the top of that container, there is a box with black charcoal/activated carbon to filter out the water completely. So, the chain is distilling -> filtering through black charcoal/activated carbon..
This is as simple as I can describe it
You can pass the already distilled water a few times more if You need double, triple etc etc distillation.
I distill water every day, so once a week You put a few teaspoons of citric acid in the stainless steel container, fill it with water and without the cover You connect the device to the grid to make the water almost boil.
You will notice that after 10 minutes the citric acid has dissolved the mineral gunk content from the bottom.
That is as far as periodically cleaning the distiller.
Cleaning is a must, because after a week if daily distilling, the bottom of the distiller is covered with minerals layer, its hard to describe the smell of the distiller stainless steel tank after the distillation is completed..
I try to always use distilled water in processing films and paper. All is crystal clear.
Reverse osmosis is a different cup of tea, not worth the hassle. Been there done that.