I'd even say making sure you have a well-constructed carrying case that allows you to keep them on your keys 24/7 is more important than any concerns about comfort or sound quality, which are still really important. Hearing protection that you don't have on you is useless against unexpected loud environments.
The consequences of killing birds and insects could be worse than the cost of keeping them around. That's what it boils down to. Knowing that, you just have to figure out if you think this is true for the things you value. You can try to figure this out yourself, or, if you think someone else could make a better judgement, see what they think. If the answer is "yes, perhaps the consequences of killing birds and insects could be worse than the cost of keeping them around for the things I value", then you should care.
Halogenated solvents should definitely be avoided at all costs but I'm generally not too concerned about how hexanes are used to extract cooking oil, for example.
IA uses some custom tools for their pdf OCR and compression, but their pdfs should should be PDF/A compliant. It might have to do with the vulnerabilities behind JBIG2 compression.
I think frequently making new primary accounts is a good compromise between preserving obscure knowledge and preserving privacy. A few times a year I'll even check my old inboxes just in case I can help someone since I myself have gotten lucky messaging inactive accounts about really obscure topics and getting a response.
You would still have to take additional measures if you post in some communities with any regularity.
