How should you handle migrating Mastodon instances?

I have been a member of my current Mastodon instance for a few years now, and I absolutely love the community there. But recently, I found a Firefish instance that I am thinking of maybe switching over to, because I like Firefish so far, and the community there is also really awesome. I figure with migrating followers, I can still be a part of both communities from the new account (especially since I mainly stay in my following feed and don't really browse the local feed.)

I'm still holding off on migrating for a bit until the honeymoon phase wears off, but if I do end up doing it, is there anything I need to/should do beyond just going through the migration process and transferring the data over? Like is there some sort of courtesy post I should make on my Mastodon instance saying I am moving over? Or am I just overthinking everything?