I find it easy to draw healthy boundaries.

A boundary is easier to say once than to hold the fourth time. Saying it takes a sentence. Holding it takes the awkward pause afterwards and the guilt on the drive home.

It helps to make them concrete rather than emotional. Thursday evening is blocked out in the calendar. The phone goes off at ten. I don't discuss my sister's marriage.

Specific things can be kept. Vague intentions about needing more space cannot. Pick the one that could be written on a calendar, and put it there.