Mocks 3 and 4 are absolutely worth using and are generally representative. I wouldn’t assume 5 and 6 are automatically “more real” or closer to the actual GMAT just because they come later.
The bigger issue is how many clean official mocks you need before test day. If your exam is soon and you only need two more data points, 3 and 4 may be enough. If you still have several weeks left, want more score confidence, or need to practice pacing under official conditions, then buying 5 and 6 is useful.
I’d use them like this:
- Mock 3: diagnose current level and timing.
- Spend several days reviewing deeply.
- Mock 4: check whether fixes worked.
- Buy 5/6 only if you still need more official practice or your scores are unstable.
Don’t burn official mocks too quickly. Their value is not just the score, but the review afterward: wrong answers, slow correct answers, timing collapse, and section fatigue.
I built a free GMAT planning tool from real debrief patterns that may help you decide how many mocks people typically used for different score paths: prepsignals.vercel.app
Short answer: 3 and 4 are realistic. 5 and 6 are useful, but not mandatory unless you need more official test reps.