Don’t announce boundaries like threats. State them like store hours.

Stated like a warning, a limit invites an argument, because a warning implies a consequence someone can test. Said like information, it is just how things are, the way a shop shuts at six and nobody negotiates with the sign. The difference is mostly in the delivery, since the same sentence can land either way. Heat makes people respond to the heat instead of the content.

Write out one limit you need to state, then take out the justification and the edge. I am free until eight, or I do not lend money. Say it flat and move on to the next thing in the conversation.