Aside from the obvious case where you don't want to sink in any more of your money fighting an unwinnable battle, abandoning the application might be appropriate in limited circumstances where there has been an early office action (e.g., expedited prosecution), where there has not yet been a publication, and you want to refile your application because you are hoping to get a new Examiner.
It is usually an incredibly dangerous maneuver, however, because you will irretrievably give up your priority date, so you are running the additional risk of facing prior art which has an effective date that is after the date that your first application was filed, but before the date that your second application was filed. Further, if you are not careful about your dates, the abandoned application could publish before your first patent application goes abandoned -- in which case, your first patent application could be used against your second patent application as prior art. This may lead you to take additional precautionary steps such as express abandonment or a request for non-publication. It is usually safer to avoid this strategy altogether.
It is usually an incredibly dangerous maneuver, however, because you will irretrievably give up your priority date, so you are running the additional risk of facing prior art which has an effective date that is after the date that your first application was filed, but before the date that your second application was filed. Further, if you are not careful about your dates, the abandoned application could publish before your first patent application goes abandoned -- in which case, your first patent application could be used against your second patent application as prior art. This may lead you to take additional precautionary steps such as express abandonment or a request for non-publication. It is usually safer to avoid this strategy altogether.