In a self-defense situation, in order to express the full potential of martial arts (traditional or modern they are) it is important to understand that:
Our body must be trained with daily perseverance (after 3 days of inactivity the decline begins)
Our training must be reasoned and focused, nothing is left to chance (we have to understand and rework every experience and knowledge learned)
In training we must express at least the 150% of what we will need in a real battle (in terms of endurance, speed, technical precision, etc.)
Our techniques (the ones we choose as the favorites) has to be tested in different situations and with not collaborative partners (once we've understood them)
We have to train body and mind to withstand the stress of a real clash
We must thoroughly learn how to manage all aspects of the fight (fight on the ground, locks, weapons, multiple attacks, etc.)
We must test our capabilities in as much as possible real situations (with proper precautions and limitations, not in a preordained way)
Although it may seem obvious, the last point must be emphasized in particular; if we want to learn to play Tennis we must play Tennis, if we want to learn to cook we have to cook if we really want to learn to fight, it is inevitable: we must fight.
As well as we never learn to cook by remembering hundreds of recipes or training us to mix the sauce, we will never learn to fight if we never get into a fight.
Let's be clear, do not wanting to fight can be a considered choice, respectable and acceptable, martial arts have many facets that are beyond the struggle (personal growth, meditation, wellness, physical outlet, artistic expression, etc.), the key thing is the do not pretend to know how to fight without having ever fought.
Can a doctor say to be a doctor after spending a lifetime avoiding the cure of people? He can not.
Any martial art if studied in a superficial way, without preparing the body, without adapting the mind, without immersing them in concrete situations (etc.) ss hopelessly ineffective in the presence of an adversary even mid-low level.
Many times we hear about ineffective martial arts, outdated styles, unsuited to the sport, to certain types of confrontations, to personal defense, too delicate techniques, too violent (etc.): these are puerile and sterile considerations.
It is not the fighting style that works or not but who studies it and then how he apply it in a more or less coherent manner (in relation to the situation). It's obvious, that there are differences and limitations but it is up to us to fill voids and distances, we need to adopt a constructive mindset: a good student / practitioner is never completely passive (even at the start of his path).