What are the pros and cons of having accounts on many instances?

i have account in two instances .
Thats how i started . I didnt give much though to it.
I guess my thought process was :
-Look an instance about programming issues. They say i’ll find there
person with similar interests. Lets make an account.
-Look another instance for general discussion. I could find people to
discuss interesting things. Lets make another account.

Now i know i can follow / search people from other instances (still i ‘feel’ that
they are somewhere ‘far’ and i have to ‘reach out’ to find them’ .So
that feels needing more time.).
On the other side i start to fill dizzy having to follow/admin two accounts.

What do you think? Did you have similar dilimma? What are the pro and cons here?