the most important thing is don't forget to save the assets you bought in your wallet. don't leave it on the exchange. for long term holding, it is better to focus on Bitcoin. and just ignore Altcoins, even if they are top 10 marketcap. because in the next few years, we will never know what will happen to the projects where we put money. what happened to FTX and Luna should teach us many lessons for choosing a project.
I also try not to keep the coins on the exchange for a long time, when I have such a need, I try to keep it no more than a few days. I feel much more relaxed when my coins are stored in my wallet. And lately I'm more inclined to the fact that I like the hold more, bitcoin in a reliable wallet gives me confidence and a restful sleep. Trading has its benefits, but sometimes it takes too much of my time.
A very good point about not keeping your assets in exchange it is safer when your assets are in your care and remember not your keys, not your coin, that is where plenty of people are getting it wrong, once any exchange decides to foldup then a lot of people will be left with nothing and you have to abide by these policies if you want to use their service efficiently, and holding bitcoin gives you that assurance of your assets not going anywhere, during the bear, not all coins survived it but despite everything, bitcoin is still standing strong what happened with FTX should be a lesson to many.
A lesson that being learned the hard way. It is a good information to always remember that using exchange is good but keeping
your asset inside any exchange a risk.
Like what you have mentioned, not your wallet also not your coin, exchange can be strong today and can breakdown tomorrow. We don't know what the future can it be.
Always be mindful with all the information and make sure you learn from each experienced that you've got.