Hi nik256,
You ask an incredibly broad question - and the answer will depend on a number of different variables, including your 'starting score', Goal Score, available training materials, capacity to learn (both content and Tactics/patterns), etc. Since the 700+ Score has remained right around the 90th percentile (going back decades), clearly most GMATers never score that high on the Official Exam regardless of the number of training hours spent preparing for the Exam. Many GMATers spend 3 months (or more) on their studies before hitting their 'peak' Scores - and it's fairly common to spend 10-15 hours a week (or more) on that process. Thankfully, the GMAT is NOT an 'IQ test' and it is remarkably consistent and predictable - meaning that you CAN train to score at a higher level. If you find that your current approach isn't leading to an improvement in your Scores, then you might need to consider looking into using other resources.
GMAT assassins aren't born, they're made,
Rich
Contact Rich at: [email protected]