Quote from: fred21 on Today at 02:39:13 PM

I use bitadress.org offline or Ian coleman wallet offline. I don't use software wallet.

That's more or less the same as using a software wallet.

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I use coinb.in offline to generate and send transaction.

If you want to be very careful, it doesn't hurt to verify your signed transaction with other software (Electrum for instance) before broadcasting it.

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I store my encrypted seed and encrypted private key (BIP38) on paper, on a drive and on google drive (3 copies)

The risk of someone compromising your Google drive is much more likely than someone randomly finding your private key.

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I always put flight mode on my computer and use private browsing on firefox before using bitaddress.org or ian coleman wallet or coinb.in.

That's another risk: malware could patiently wait until your computer goes online again. Using a LIVE Linux DVD that runs only from memory (obviously offline) is much safer.

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And I always close firefox, delete unemcrypted files, empty the trash before removing plane mode on computer.

That's probably safe, but you can't be absolutely sure. The computer you used to handle offline keys should never go online again.