I have several lamps that I keep for emergencies, and even when they are completely out, the oil evaporates. But, when the lamp is not out, and just glowing,you get a heavier smell of combustion, and it is difficult to tell if it is out without looking, which is why I have a small hand mirror I use to look down the chimney at the wick, on the wall mounted lamps. the other lamps I can easily pick up, I just pick them up and look. Another thing I like to do, is to lower the wick about 1/8 inch below the wick tube, to slow evaporation of oil. Even so, after a year, a wall lamp may lose all of the oil in the reservoir to evaporation, and it will need filling again. It must be the oil isn't as heavy as it used to be, or I am just lucky, and not having to light the lamps very often!
I'm planning on some more videos. I started a new job in February and getting settled in with that temporarily took the focus off the fun things. Thanks for asking! Have a good day.