Holding my coins on the offline wallets for long-term holdings. I think offline wallets are best for holding coins safe. For short time holding and trade, I hold my coins in different exchanges.
that is the most secure way of holding coins storing it on the offline wallets like hardware wallets, I have a worse experience in storing coin in an exchange, the exchange delisted the coin that I am holding for almost a year so it is not advisable to store coins in exchange for holding.
I think it depends on what coins you hold, but holding coins with low volume have risk to get delisted anytime. And before it get delisted, we member get notification which coin will get delisted so we can take action with that coin.