The clearest answer may take the longest to formulate.

A short clear answer usually costs more work than a long muddled one. You have to know the subject well enough to identify what is essential, decide what to leave out, and take responsibility for the omissions. Length is often just unfinished thinking passed along to the reader. The compression is where the effort went.

When you have written something, try cutting it in half without losing the substance. It will be harder and better. Give yourself time for that second pass rather than sending the first version.