Bitcoin and Ethereum for sure will be held in my wallet. I also sold a few of my altcoins which had a good rate of increase lately such as with few amount of meme tokens, slp, and the others. Was really happy that the market prices of those altcoins managed to have a good price recovery for a short period of time however, as we all know, nothing is too unrealistic to be having a consistent uprise movement, with large rate of increase, for a long period of time. There will always be a tendency for a sudden market crash especially for those tokens which are too volatile. Only major tokens are ones which can resist and slow down the decrease a bit, which makes them a safer coin to hold in my opinion.
A tip of advice via experience is that AltCoins ain't good to hold for long and may reach a total lost peak of you tends to hold til you reaches its ATH. So I chooses to sell once I'm comfortable with he profit it may offer in the main time. This not like the bitcoin that you can hold longer and so also the more profits it offers.
Indeed, what's important is to be aware of your risk appetite and to be realistic of things by means of learning from the past and what the chart says, basically. It is okay to desire big profit from your investment but never be too greedy to embrace that much of risk you are not even ready to take the consequences with. Manipulation of the big investors will be always a threat for you to watch out if you are after long term holding with altcoins. Enough warning for you to not be too confident just because a bullish pattern is observable.