For a person who has never had an impulsive personality, a single impulsive act would be shocking or surprising to friends, co workers or family who know the individual as a stable, regular soul who never does anything on a whim. Instead, the person has a history of planning and budgeting for each and every major decision in life. Common sense and popular advice tells us that any sudden and significant change in behavior signals that a problem might be developing, that the person might be having a "nervous breakdown", or that the person might need help.
The aging person might actually be experimenting with their behavior and attempting to do more things that are spontaneous, having been bound by a life of regularity and rigidity. Most friends and family would keep an eye out for more "spontaneity", looking for even more ominous signs that something is completely wrong with the person! The fact is that a major life event can trigger a true effort to change lifelong personality traits and behaviors. Such changes are not impulse control disorders when the outcomes are positive and not harmful to the self or others.
A major accomplishment, the death of a close friend or loved one, or a major financial gain or setback, or even a change in a long term relationship can trigger a person to do serious self examination and to experiment with other ways of being. A spontaneous and impulsive person might become more regulated by experimenting with obsessive attention to detail while a regulated person might become more spontaneous by experimenting with impulsive acts.
With true and profound impulse control disorders, the onset is commonly in childhood, between the ages of 7 and 15. The impulse control disorder, if left untreated, has been a problem for a while. The disorder might be mild enough for the person to live a normal life, or it might be profound enough to trigger external or law enforcement intervention and orders for treatment.
The impulse control disorder involves repeated failure to stop behaviors that give short term tension relief or gratification, but at great cost, because the impulsive acts are self destructive, harmful to others, harmful to property, or are financially damaging. Even when the person wants to stop the action and has tried to stop the impulsive acts, they have repeatedly failed.
The true impulse disorders are pathological gambling, hair pulling, skin picking, kleptomania/stealing, pyromania/fire setting, and explosive disorder, where the person cannot control their temper and assaults people or damages property. There is some way in which these behaviors became a way to relieve tension, so that when tension arises, the impulse is to do the problematic behavior in order to relieve the tension. In other cases, gratification or obtaining a pleasurable result is the goal of the behavior, no matter how harmful the behavior is.
A loss or lack of control is the primary factor of impulse control disorders, but there may be other disorders present, including maladaptive thought processes and actions, substance abuse and sexual disorders. A healthy person will find ways to manage drinking, maladaptive thought processes that develop and sexual proclivities so that they regain control.
In other words, true impulse control disorders will probably manifest at a much earlier age than is indicated when a single impulsive act becomes a concern later in life. It is the repeated failure to control the impulsive acts that result in short term gratification, but long term harm that make the impulse control disorder greatly different from the desire to commit an impulsive act on its own. But gambling is one area where a person can transition to pathological gambling after a lifetime of well regulated gambling for sport
When any person, regardless of age, undergoes any rapid, major and consistent change toward problematic impusive behavior, it is cause for concern that they have suffered a problem, or are undergoing trauma and might need medical attention and treatment. In those cases, more observation and possibly intervention is called for.