With the unfavourable market conditions we have seen in recent times, I think that the best time to buy a coin especially for long term holders is in an exchange after the ICO, price usually falls then and you can get it quite cheap.

On a PreICO or ICO. And I'm still sure about it if we are talking about a long term investments.
Let's take for example DexAge ICO. The price now is 0.01$, and also you will receive 20% bonus in tokens. And this is great. Also if take exchanges tokens, they are only keep grow in a price. So that's why I think take part in ICO is a good idea.

I am sometimes confused, when I want to choose good coins (potential). I have a plan to trade as far as small scale capabilities. My question for now is how to find out or analyze good coins and not. By having a good long term. Please share your experience. I really appreciate each of your opinions.
Thank you very much.

I think that OP already understood from the answers that the best period to invest in crypto already has been started. The coins recover slowly and the prices go higher, so buy it right now.

I think the best time to buy Altcoins is when they Havel isted in an exchange, but you have to be careful because not all coins work with this strategy.

First, if you want to buy an ICO coin, and if you feel that the coin is really good, then buy it at ICO because it is feared that the coin will run out during the ICO, but if you doubt the ICO coin, then buy the coin when in the market.

An example of the last year ICO go   very low in terms of profitability, if you want to find a good project, choose very carefully.
 For me, decentralized exchanges are promising.

I think it depends on the altcoin itself. Buying in the early stage of ICO may be profitable as you can get big bonus and it won't get dumped very big if the project already has working product. I once invested in very early stage of an ICO in 2017 where the bonus was big and when the altcoin hit the exchange, the price got dumped but the bonus i got from investing in early stage still gave me profit. But in this long bear market, buying the dumped good potential altcoin is the best choice to me.

The first option is more profitable but very risky. The second and third options are quite safe but profit is not guaranteed because the time you are buying the coin from the exchange might not be the last dip. Prices might go down a bit further and will not rise again to your buy price.

Waiting for a dip is the best method of how to get tokens for the best prices. It makes much more sense, because within a short period of time tokens are getting less valuable and you will get your chance to save money.