The usual advice is to sit on a post for an hour and reply to everything, because engagement in the first hour decides its fate. The instinct is right and the explanation is a bit mythological.
What early activity means to a platform
A post is shown to a small group first, and how that group behaves decides whether it gets shown to a larger one. Comments count in that, and a comment is a stronger signal than a like because it costs more to leave.
Your own replies are comments too, but a platform can tell the difference between a conversation and an author padding their own count. Forty replies saying “thank you!” is padding. It is also forty notifications sent to people who now know that engaging with you earns a form letter.
What a reply is genuinely for
- Answering the question, when someone asked one — this is the whole thing, and it is often skipped
- Making the next comment more likely, by responding in a way that has somewhere to go
- Finding out what people did not understand, which tells you what the next post should say
A reply that adds a sentence is worth twenty that add an emoji. The second kind teaches your audience that commenting produces nothing.
The scheduling consequence
If replying early matters, then posting at a time you cannot be present is a real cost. A post scheduled for the middle of your workday, or the middle of your night, goes out into its most important hour alone.
This is a good argument for fewer, better-timed slots. Three posts a week you can show up for beat five you cannot — and the schedule should be built around the hours you are actually available, not only around when the audience is.