It's absolutely one of the worsts day that is going to happen if you lost all your bitcoins. That's why I put it now on electrum where I have the seed, private keys and master public keys and I can recover my wallet any time. So for you people out there that is still not prepared before August 1. Make sure that you hold those keys.
I am sure that you wont loose you coins but you might loose the benefits of the split as usually you are supposed to get coin on a equal ratio of 1:1 if there is a split and if you save your coins in exchanges then you wont get those but that does not mean that your coins will vanish because the coin with the biggest followers will be the leader and that will be the coin you will be getting if you store your coins in an exchange.
Yeah , here I also support that holding the Bitcoin for long time is not a better way of investment of your money , because only price increases in the Bitcoin not the amount , amount will remain same as it was earlier .
So more better way to invest to your Bitcoin is the trading , because at one side you will bought the coins and at other side you will invest in altcoins to make the amount increase slowly slowly.
And second thing here to put money in the exchange is not safe , I am.not saying at risk but reality is that we can't make ourselves free that our money in the exchange is fully safe ( fear of the robbery of eth coin at many exchange in past ) , so if you want to go for long term investment then more better will be to put your money at the the direct address whose private key is in your hand .