The answer is simple.

Are you a trader? If yes then you need to left your coin on exchanges to trade.

Are you a holder? If yes then you should deposit your coins in a safety wallet.

Leaving coins in exchanges definitely involves risks, if the exchange closes for some reasons (scam, bankruptcy, ecc.) you will lose all your coins because you don't own private key. On the other hand, you have a better management of all the coins.

Private wallets are obviously a safe option to store your coin because you own the private key, but it involves to get many different wallets.

If you are looking to manage just ERC20 token I suggest you open a MyEtherWallet address, you can easily handle all the ERC20 tokens such as deposit into exchanges, withdrawal from exchanges and transfers.

Hi. If you are going to trade much better keep it on exchange. But if you're going to invest on long time it should be wallet. So you should create some strategy before chosing.

If you want to trade some of your digital assets the you can put into exchanges. However, if you want to hold the rest of you assets then you must use your cold wallet where you have the full control of. Keep in exchanges sometime make you feel scary of getting compromised.

iI preffer Wallets to exchange for a sole reason that they are safer than exchange, wallets also gives you control of your coins and ability to verify transactions before completing them

I think the best way and safest way for you to avoid a bigger lost if hacking issue occur is to devide your asset into both wallet and exchange. It is simply unavoidable for hacking issue to occur specially when your luck runs out then the best option is to set a way to make your loss lessen to minimum amount.

Just want to suggest to always use your wallet, keeping balance in an exchange is very risky to lose, with you having full control on a wallet then your balance will be much safer than keeping a balance on an exchange.

if you decide to hold a coin, use wallet. If you want to trade your coin or sell them in a short time, use exchange. In somehow, exchange is still better than wallet although it does not have a good security. If you do not want to lose any of your coins in any case, use wallet

If you don't own the private key - you don't own the coin, it's as simple as that.

Store in your own wallet, and trade on decentralized exchanges (IDEX, etc - there are a lot more coming out, I believe binance are developing one).

is it dangerous to save or store your all coins in the exchange, I am not sure to store my coins in the exchange is not really safe
but not wrong if you want to save it at exchange for daily trading.

Both have its different functionality and connection with each other. In terms of safety you should keep it on your wallet if you also want a long term you have full control on your coins. Exchange is the fast way to sell your coins and after that you still need to keep it on your wallet. So in short, it depends on what are planning to do with you coins, long term investment or short term always trading.