The decision about whether to use a tutor — and which tutor — is the single biggest variable cost in 11+ preparation. Many families spend £3,000 to £8,000 across the year; some spend nothing and do equally well.
The short answer
A tutor is useful if (a) you do not have the bandwidth to sit alongside your child four times a week, (b) your child responds better to a non-parent voice, or (c) the test format is one you cannot easily learn yourself.
The longer answer
A tutor is not necessary if (a) you can commit time, (b) your child works well with you, and (c) you are willing to learn the format yourself. A motivated parent with the right materials does as well as most tutors.
When picking a tutor: ask for the format-specific result history (not generic "11+ pass rate"), confirm the tutor uses materials in the right format for your area, and meet the tutor before signing on. The relationship matters as much as the technique.
What experienced parents do
The most experienced parents either do it themselves with a workbook + paper subscription, or pick one tutor for one weakest subject only — typically the weaker English or Maths — rather than a tutor for the whole 11+.
What to avoid
Avoid: tutors who charge a premium without sharing materials between sessions; "guaranteed pass" promises (no honest tutor offers these); and group classes larger than four — the per-pupil attention drops sharply above that.
Practical next step
Decide tutor or no-tutor by the end of the summer between Year 4 and Year 5. Bring forward your decision rather than drift into it; mid-year tutor changes are usually painful. A small, deliberate action this week is worth more than a grand plan for the year ahead.