Why X’s count differs from a normal character count
X weighs characters. Latin letters, numbers and common punctuation count once. Emoji count twice, and so do characters from scripts like Chinese, Japanese and Korean. Every link counts as 23, however long or short it is, because X shortens it.
So a post can look short in a normal counter and still be over the limit on X. This counter follows X’s published rules.
Threads that get read to the end
Make the first post stand on its own — it’s the only one most people see. Then let each post end on a reason to read the next. Breaking at sentences, not mid-thought, keeps the thread readable.