If you are a trader and short term holder of coin then exchanges might be an option for you, but if you are long term holder then wallet is a good option for you too. So it depends on the category you belong to.

now les make it this way; if you leave your coin on exchange what will happen to you if you find out that the exchange is no longer there or trading.. this implies that you have loose all your token for that particular exchange were you dump the token.
secondly if you create a wallet for that your token; what if the wallet is being hacked, what do you thing will be your benefit?

now the best thing to do is that "you will create a particular wallet for a particular token or for each token you have in your wallet so that if one addressed is being hacked you still have some reserved token in the next wallet.

I think this is helpful to you.

Since only you know your private key, a wallet is better for you especially for the coins that you decide to hodl for a long time. I believe it is also better to have some BTC or ETH in different exchanges not to miss any opportunity.

On the exchange, it is recommended to keep only those coins that you use for day trading.  And the altcoins that you Hold, I recommend deducing on wallets, which are intended for these coins.  You can also try multi-currency wallets, for example, jaxx.  If you keep money on the exchange, then use more than one exchange.

If we are talking about the storage of funds, then the best solution will be to use hardware wallets, because they will be able to help you secure yourself as much as possible. But you should never keep money on the exchange.

Exchanges cons,
1. You don't own the private keys of your wallets
2. Most are unregulated and uninsured

Wallet (Hardware) cons,
1. Not free
2. You may lost it(by not storing it in a safe place)

So in conclusion, I prefer hardware wallet.

please suppose that i have a gold store, and also you have some golds. is it safe to hold your golds in your home box or in gold store? it is clear that in your home you have good access to your golds. but if gold store rub or ban your golds, you can not access your golds. i perfer to hold my coins in my own wallet

Totally agree. It's quite dangerous to keep investments on exchanges. They exist for trading. For purposes of storage it would be wisely to keep coins in wallet. But if you do want to use exchange, pick one that uses cold storage and two-factor authentication. I know of cex and bitstamp, are there any others?

I believe that it is much safer to store its cryptocurrency on purses. Since, if you keep your coins on the exchange, then your private keys are kept at the stock exchange. And from private purses private keys are only with you.