Check comment length against limits.
Comment fields have a hard character limit and, separately, a soft threshold beyond which the platform collapses the text behind a Read more control. The soft threshold is the one that affects whether your point lands, because a collapsed comment loses most of its readers at the fold. Reporting what share of your comment falls above that threshold makes the trade-off concrete: a 600-character comment on a platform collapsing at 280 shows under half its content by default. The practical implication is to put the substantive point first and the qualifications afterwards.
Headroom
Remaining = platform limit - comment characters
Visible share
Visible % = min(length, collapse threshold) / length x 100
Because it determines what people actually read. Most readers scroll rather than expand, so anything past the fold reaches a small fraction of the audience. Your first sentence has to carry the point on its own even when the rest is technically present.
Usually not — threaded replies to yourself read awkwardly and often get collapsed as a group. Tightening a long comment is almost always better, and if the content genuinely needs the length, a short comment linking to a fuller write-up works better than a wall of text.