All I can really say is that different people have different abilites - some are better at math than verbal. Also, within these sections different people have different weaknesses. ALSO, different people grasp concepts at different rates - some get it right away, others need three or more examples before things "click."
I think the best thing to do is to take a practice test and/or a diagnostic test from the Official Guide to GMAT Review 11th Ed. and see how you do. Then, identify your areas of weakness and target these as you further improve your strong areas.
I have seen people on this forum who prepared for two months and scored well over 700. I have also seen people who practiced for months and cannot break the 500 mark. Then, there are people like myself, after about 4 or 5 months of practice all we can manage is a 640 to 660.
FINALLY, as we all obsess over the GMAT score, I think it is important to keep things in perspective.
Your GMAT score is only one of many variables that determine whether you are admitted to a certain school or not. I love the following story because it shows that you can get in to a very good program with a low GMAT score as long as you strengthen other areas of your application:
https://www.beatthegmat.com/admission-su ... t8107.html
Remember, you can be rejected from Stanford and Wharton with a 720 if other areas of your application are weak. You can also be admitted to these schools with a lower score if other areas of your application are strong.
I would actually go as far as saying that your essays are more important that the GMAT. Your GPA and GMAT score are evidence presented in the admissions court. However, your essays speak for you and make a case for how this evidence should be viewed and what other variables must be kept in mind.
That's all I have.