The Importance Of Air Circulation

Hi i am a first time grower and i have my first plant, i have one in my wardrobe and was curious as to how necessary air flow is for one plant.

I read somewhere before that for one plant in a wardrobe, leaving the door open a bit is enough, but it seems kinda unrealistic..

If i don't need good air circulation yet (1week) i obvoiusly will as the plant gets bigger, i intend on moving it out of my wardrobe when it gets bigger and having a fan on 24hrs but when should i start?

Thank you

I have a fan on mine after the first week.