Not your keys, not your coins (money)
SIMPLE AS THAT.
Similar to a bank account number, Bitcoin and other cryptocurrencies uses public/private key to secure transactions.
The public key is an equivalent of cryptocurrency receiving address. Private key is crucial, anyone that has access to the private key can access to all funds on the public key.
In short, if you lose your private key, you lose your coins.
At SPARTAEX, we create cold wallets without ever exposing them to internet, to provide security to all clients funds, however we encorage all clients to withdraw their coins to their wallets.
In short: with SPARTAEX, you coins are safe in cold wallets, but we recommend to withdraw all coins that are not intended to trade in next 60 days. Why? Do you carry your wallet with your cash around or you leave it at the bank?

Where can you safe store your coins?
There are many hardware wallets like Ledger, Trezor, paper wallets…just search on the internet.
Hardware wallets are convenient, affordable, portable, easy to use and backed up by a paper wallet allowing easy recovery in case of loss. If you have any significant amount of crypto, using a hardware wallet should be a no brainer.