As a radar controller working approach, the set up for your final vector is just as important if not more important then your final vector.
For an aircraft on an ILS approach, you’re going to clear, then want that aircraft to be on one clear heading not turning for one nautical mile or more. So clear, turn to final, stop their turn, capture the localizer, intercept.
By giving yourself room you increase your chances of a perfect intercept. So if you notice you are clearing to early or late, either clear the aircraft further down the localizer or extend downwind a bit more to compensate.