When it looks about right, to me......depending on which it is of the two types I currently fly - Tiger Moth or C152. To be frank, I have no idea what my hold-off height is, at my small level of experience. I do know that I generally get a smooth arrival (in the 3-point attitude
) so whatever the height the seems to be, minus the distance from tyres to eyeline, is my hold-off height in inches. Simples!