If you have begun your research into becoming a licensed private pilot then you have discovered that there are two major training segments that you must complete. First the pre solo segment then the post solo segment.
Of course, it stands to reason that there are many things you must learn and become proficient in before you attempt your first solo. After all, once you reach this stage there is no room for error. Safety no matter what segment of training you are at must be the priority.
Qualified flight instructors are very adept at judging whether an individual is ready to move onto solo. If they are not at that stage yet but have completed the pre solo segment then that particular student can be moved onto the post solo requirements. Although this is nothing something many schools will do, it is a very feasible possibility. The solo hours can be concluded after this part. Quite often, the biggest stumbling block to not flying solo is the insecurities experiences with the landings. In cases such as this, extra flights are a good solution. This is where an added expense may occur if you did not count on extra flights.