Writers avoid long, complex sentences and refine for conciseness.
Readers are willing to understand.
Writers are willing to find answers to their own questions about grammar, mechanics, usage, diction and content. The English language reflects the needs of the people who use it, past and present. The rules of grammar are basically interpretive and subject to change with little or no notice. This requires writers to know what they mean to express and so, how it can be made clearer. Because writing reflects thinking, writers should be able to account for the technical elements and the content choices in their writing.