I use roll on deodorant and some brands have transparent cases/bottles but some others don't so I cannot see how much is left inside in order for me to buy a new one on time.
Is there any hacky way to know if a roll on deodorant with a non transparent bottle is about to finish?
UPDATE: Just realized that the picture I had posted was for a 'stick' deodorant. I updated the picture. I am talking about deodorants that have liquid inside and a moving ball on top and are not transparent like in the picture.