I keep my bitcoins and altcoins in trading website like yobit, cryptopia, livecoin, etc. because this websites are user friendly.
Are you sure that you are keeping your bitcoins at yobit.net? There are a lot people that are complaining about that trading site. So if I were you, think again because in the end you will have problem on it when you are experiencing withdrawal problems.
There is an opinion that you need to keep your wallets on a flash drive, because it gives you the opportunity to save your money and prevent unauthorized entry into the wallet. Of course Which currencies to keep their coins is already a purely personal matter, But I would like to hear advice.