Well if yoy are going to do some short term investmeng why not put it on exchanger so whenever it pump you can just convert right away but if you are doing some long term investment why not put it on wallet for much more safer

Saving all the coins in one exchange for me is not very recommended, because saving in exchange is very risky.
If you want to save on an exchange, better keep it on a reputable exchange but you should still review it every day to keep funds safe there.
I would recommend saving funds on a wallet.

According to my opinion you should keep your coins and tokens in their respective wallets like bitcoin in its wallet, ERC-20 tokens in its wallet or NEP-5 in theirs, etc. Keeping your cryptos in the exchange can be quite risky with all the hacks and all. Recently, my friends binance account got frozen due to unknown reason and he had all his cryptos in that account.

Some users set a separate purse for each crypto currency (for example, Electrum-Dash or Ethereum Wallet). This approach undoubtedly provides a safe way to store digital currencies, because each of these wallets gives you the opportunity to control the private key. If the latter is stored in a secure place (for example, written on paper and or stored on a flash device that is always offline), then you can be 100% sure of the safety of digital savings.

Exchange is way too vulnerable to hacking plus your coin activities is pretty much exposed, wallets are safer bet as you can chose which one works for you and encrypt it in your own liking, always stay safe

If you do not trade in crypto currency, but just want to buy coins and keep for a long time, then ideally you will need to create wallets for all the crypts you bought and store them there. If you trade in crypto currency, then keep it on the exchange.

At the moment I keep my coins on the stock exchange, because I tried to start trading. Also, I keep them there in case the market dump to go to the tether.

wallet is best for long term coin hold.but if you want to  trade you must use exchange

wallets are much more safer of course. there is less possibility to being hacked etc. but you can not act fast when you put them to wallet. in exchanges you can put sell orders and stop losses that has very good benefits for traders.

Exchange is a website that handles the transaction of bitcoin or other cryptocurrencies.
Bitcoin wallet is a provided service where you can store your bitcoin securely.