A difficult question, here everyone decides for himself what he wants from the coin.
if I correctly understood the question, do you want to know, it's better to exchange different tokens into one coin or create a purse for each of the coins ...

1. Consider the option of transferring all coins and tokens into one, more weighty ...
Let's say you have 20 different tokens for some amount (say "N" of the etherium), you can exchange tokens for this eth, or you can keep them in coins. It all depends on the tokens, and on you. The tokens will jump in the price upside down (more often down), ask yourself if you are ready to hold tokens so that they grow in price, it can happen tomorrow, maybe in a week, a year or never at all, so the token may fall in value, or even generally depreciate ... From what it follows that your amount of "N" tokens also changes. This is a kind of game in which you do not know where the course will go, so it's up to you to keep tokens or exchange for ethereum and keep them on the eth, but remember that in the reverse order, you can exchange the ethereum for tokens. But do you need it ?!
2. Consider the option to keep all the tokens on different wallets and not to transfer them into one expensive coin. You need a lot of time (at first) to track the course of each of the coins, you must understand that the coin may fall tomorrow or it may rise, it needs to be tracked ... Of course, let's take Forex, for example, there teams of professional analysts can not predict the dollar ... one dollar only for a while, and you will need to track dozens of different coins, all alone. Of course, sometimes the expectation of yourself pays off and the coin you saved and continued to grow will bring a very good amount, and you will be happy, but read the forums, ask the Holders, I think that such a percentage of tokens is very low.

Following from this you decide what to do, do not take the advice of other people, it's luck. Someone is lucky, some do not, and it's better to spend more time and understand what's what, read various materials.

This is all my personal opinion, someone might disagree with me. I hope you will benefit from my answer if I understand your question correctly!
Good luck!

This is according to your purpose bought that coin, if you would like hold by long term will be much better keep your coin in personal wallet that you own the private key because this way will be more safe than keep in exchange. But if you just want to buy and sell in short term will better keep in exchange so will be efisien and dont forget to use all security feature.

For me i would put my trust in walet. It is not that i dont trust exchange wallet. Im just avoiding case like exchanges being hacked.  That incident is very common nowadays. And im not risking my chances

I usually keep it in trusted and safe exchanges ie Bitrex and Binance because I'm a trader but that depends on the coin I have. If it still does not enter that in list then I keep it in MEW and it's integrated with authentic Ledger with double protection. I advise anyone who wants to keep their coins safely using ledger its worth it. I have tried it

A combo of both?! I like to do a combination of exchanges and hot/cold storage.  In order to increase my liquidity and access to the market at all times, i like to spread coins across multiple exchanges and limit the amount I keep in each one, reducing my risk exposure.  Large majority of coins should be held in a secure hardwallet like trezor or nano ledger.  Furthermore, temp storage of ERC-20 tokens on meta, myetherwallet can create flexibility and liquidity along with the integration of hardwallet verification

If there is good wallet for the coin/token - of course wallet. But sometimes the coin wallet is a piece of shit with many technical flaws, so in this case use few  exchanges.

I think to save altcoin so it can be safer better on the stock and even then if the listing, but if still not better on the wallet only because the wallet already has a private key and this will provide security to altcoin that we have.

I think this problem depends on each person. If you are a trader, you should keep them on the exchange site because it will be very convenient for your transaction. And if you do not trade often, you want to keep them to get profitable, then I recommend you store them in wallets, it will be safer. And there is a note that when you save Bitcoin and other altcoins on the exchange site, you need to enable 2-step verification, enabling maximum security settings to avoid hacker invasion

i refer to you probably wallet is the better option because it is safe and less chance to stolen your altcoins. yourself keep your private key then only it is safe. in exchanger you are giving private key to the exchanger. so better keep your altcoins in wallet. then only it is less risk.