Sade Sati literally means "seven and a half". It is the period when Saturn moves through three signs in a row around your Moon sign: the sign before it, the sign itself and the sign after. Saturn spends about two and a half years in each sign, so the whole cycle lasts about seven and a half years.
The three phases
Rising phase: Saturn in the 12th sign from your Moon. Expenses, sleep, travel and distance from home can come into focus, and many people feel the first pressure to reorganise their lives.
Peak phase: Saturn over your Moon sign. This is the most intense stretch for the mind. It tends to test patience, relationships and routines, and it also rewards steady, honest effort.
Setting phase: Saturn in the 2nd sign from your Moon. Money, family and speech are highlighted. Pressure eases, and the results of earlier work begin to show.
How often does it come?
Saturn takes about 29 to 30 years to go around the zodiac, so Sade Sati returns about every 30 years. Most people experience it two or three times. Many astrologers say the first, in youth, is about learning, the second, in middle age, about responsibility and the third, in later life, about letting go.
Shani Dhaiya (the small Sade Sati)
When Saturn is in the 4th or 8th sign from your Moon it is called Dhaiya (two and a half years). The 4th is sometimes called Kantaka Shani and the 8th Ashtama Shani. They are shorter and are usually said to be milder than Sade Sati.
What helps, traditionally and practically
The traditional advice is gentle: be punctual, keep promises, respect elders and workers, help people who have less, and keep simple daily routines. Many people chant Hanuman Chalisa or the Shani mantra, or light a lamp on Saturdays. None of it needs money. The practical version is the same: save a little, avoid big risks and shortcuts, look after your health and sleep, and finish what you start.
Be wary of anyone who asks for large payments for Sade Sati remedies, gemstones or rituals. Saturn is not appeased by spending money.
It depends on your whole chart
Whether Sade Sati is hard or helpful depends on where Saturn sits in your birth chart, which dasha you are running, and what else is happening. Many people say they built their careers during it.