alt Hacker NewsFoam: cheap, scratchy, ineffective. This one will give you abrasions sometimes.
Silicone: expensive, effective, fussy.
Wax: cheap, effective, disposable. (Needs warming up, slight drawback.)
Replies
I have like 20 brands of foam earplugs in my drawer, 5 different pairs of custom silicone airplugs, unusual earplugs from Kickstarter like [1], and so on. What I'm saying is I know my way around the earplug block. Here's what I'd write for your categories:
Foam: The most effective, by far. I suspect many people wear them incorrectly and do not insert them far enough. You can use lube (they make special ear lube for stuff like hearing aids, although I think anything medical grade will do) if you have difficulty doing so. I have unusually small ear canals; the most comfortable and best I've found by a mile are Mack's Ultra Soft Foam Earplugs. These are much more comfortable than slim fit alternatives and also have very high attenuation.
Silicone: expensive (but they're reusable and last years), but the least fussy once you get them. They are moulded to your goddamn ear---it's a perfect, pressure-free fit every time and they go right in. Drawbacks include lesser attenuation and attenuation that isn't immediately at 100%---it takes a while for it to "seal". I abadoned these once moisture started to accumulate between my ear canal and the plug and I'd hear it as I moved and it became very annoying.
Wax: joke attenuations compared to foam, and bad compared to silicone. The most expensive long-term unless you're serious about reuse. Somewhat fussy and may fall out. Very comfortable (little insertion).
Foam + wax: this is what you really want if you care about maximum attenuation. My ear canals are slightly too short to comfortably insert an entire Mack's earplug, so I snip the ends off mine, lube them up, and insert them completely flush into my ear canal. Then, I take a wax plug and mould it on top. It's perfectly comfortable and it performs better than any other option I'm aware of. I tend to also wear a Bluetooth sleep mask and play rain sounds on 100% volume and it just comes through the double earplug situation to mask any very loud/spurious noise. To remove the flush-inserted earplugs, I use a pair of blunt tweezers.
When I used slim fit foam earplugs I'd routinely get ear infections. Switching to silicone fixed that, but suffered from the aforementioned issues. With the ultra soft earplugs + wax method I never get ear infections. I make sure to always insert a fresh pair (but I reuse the wax ones for a few days) and to always do so with clean hands. I think the infections are due to friction between the plug and the canal during insertion as well as plugs that are too large/exert too much pressure once expanded---the lube and very soft plug addresses those issues.
As someone who has been wearing earplugs for decades for motorcycles, firearms and other loud events, this information at face value is a bit off.
Foam by far has the most effective NRR. Silicone and wax are fine but will not provide as effective of NRR. That said, if it’s for sleeping silicone and wax are probably fine. I would argue that foam is not scratchy at all but I usually buy more expensive brands like Mack’s and it’s good to try out different sizes.