Clearing space and time out of our busy lives to do silent retreat is part of the Buddhist way of life. In Theravada Buddhism, the three-month Vassa retreat is an annual commitment for all monks and nuns, and in some countries laypeople can choose to take temporary ordination and also do the Vassa retreat. Many Ch’an and Zen monasteries arrange for short and longer retreats for their followers. And in Tibetan Buddhism many serious practitioners engage in a three-year retreat at least once in their life. Others do short retreats, from one day to a month, while a small number of yogis dedicate their entire life to solitary retreat.

Why do retreat? Sister Ayya Khema, a Theravadin nun, explains:

Meditation retreats are a time for introspection. Because they are held in silence, except for Dhamma talks and questions, the mind becomes more and more used to mindfulness and concentration. This gives added impetus to the hearing of Dhamma, so that the truth of the Buddha's teaching can leave a lasting impression.

The time spent in retreat is dedicated to meditation and prayer as well as study of the Buddhist teachings. It provides the opportunity to go more deeply into the Dharma so it becomes a lived experience.

Retreats began in the Buddha’s time and have continued in most Buddhist traditions ever since. The challenge these days for Buddhists in the West, and in modern societies, is that employers and families are unlikely to support the idea that someone can take off and do a period of retreat. By contrast in the Buddhist country of Bhutan it is socially accepted that people may wish to do a short retreat for personal reasons, for example after someone close has died. Nevertheless, many Western Buddhist centres offer short retreats and people use their paid holiday time to do them.

For background on the Vassa retreat in Theravada Buddhism see:

https://www.learnreligions.com/vassa-450114