Your eye will compensate for it being a little out of focus. But it will eventually fatigue and not always maintain focus. To help get it right, view against a blank background, and open your eye and quickly evaluate if it’s in focus. Do not stare at it, very quick glance only. I know when focusing the diopter on a night vision device you turned it counter clockwise until it was blurry, then slowly clockwise just to the point it became clear (multiple adjustments quickly glancing each time). Any further and while it was still clear your eyes were having to accommodate resulting in eye fatigue and a headache. I think scopes go the same direction.
