The other night before going to sleep, I was thinking literally about material possessions that are essential to my life. I can't think of anything more necessary to my quality of life than these ear plugs.
After the first few nights, I got used to the sensation of sleeping in earplugs, and now I am hardly bothered by the people in the apartment next to me, only separated from my bedroom by a very thin wall. (To give you an idea of the thinness of the wall, I can tell you that my neighbor watches a lot of history documentaries (about World War II and baseball) and that he does not want to have children and that he does not cover his mouth when he belches.)
Another great thing about these earplugs is the clarity of instructions on the back. I never knew how to correctly insert an earplug before.
Mack's Earplugs are available in most drugstores in packs of 32 for around $4.25.