Mark Kleiman extols the virtues of earplugs, primarily in the context of air travel (which seems like a good idea to me). I keep earplugs on hand at home, because even a small amount of ambient noise (especially if it’s irregular) will wake me up, or prevent me from falling asleep. (The range of conditions necessary for me to fall asleep is inconveniently very narrow. Fortunately I am at least immune to the sound of the BART train passing by.)
What Mark doesn’t mention is that while earplugs are excellent at reducing broadband, continuous noise–airplane engines, vacuum cleaners, the various pumps used to run a dilution refrigerator–they aren’t so good at packets of low-frequency noise: music with lots of bass, barking dogs, and often human voices. Mark advises,
Earplugs also come in handy in hotel rooms with thin walls, and on Saturday night if your neighbors share the widespread belief that the fun level is directly proportional to the noise level.
but in my experience earplugs offer only a little relief in situations like these. (In fact, the barking of the dog across the street from me, which begins every morning at dawn and continues unabated until sometime after I leave for work–or occasionally, as late as midnight–is fairly unattenuated by earplugs, to my infinite annoyance.) Ogged mentions noise-cancelling headphones, which might be better at blocking noise packets; due to the substantial price of such devices, I haven’t had occasion to test this.
(Mark also gets decibels wrong; 10 dB is a factor of ten in power and about three in amplitude, but it would be very pedantic for me to point this out.)