I understand alarplasty is usually done alongside septo/rhinoplasty.

An alar plasty can be performed as part of a rhinoplasty procedure, or as a stand-alone procedure  when patients only wish to have the nostrils narrowed.  A septoplasty is performed to improve airflow in the back of the nose, and is usually performed for medical necessity.  A septoplasty will not change the shape of the nose.   For more information about the differences  between a septoplasty and rhinoplasty and many before and after examples, please see the link and the video below

Typically they are indeed done together. If someone decides do alter the alae at a later date, I would want all tissues/scarring to be soft and stable before doing this. At a minimum, I would suggest six months and possibly longer.