What are your thoughts on this? Personally, I keep all my BTC in a single hardware wallet. I’d like to know, from the Bitcointalk community: do you think the saying "don’t put all your eggs in one basket" also applies to those using a single hardware wallet?
I don't think if there is any need to think much about this. Everyone has their personal opinion and decision on how to store there assets. Although it is good to separate your Bitcoin assets into different wallets. And this could be either keeping the majority of the asst into a hardware wallet like trezor or ledger nano, and the lesser amount of BTC in the software wallet or hot wallet like the electron wallet to be easily accessible at any given time or for convinence transaction. But apart from that it is allowed for anyone to separate or diversify there portfolio into two different cold wallet as it pleases the person in question.