According to Ashrama System, there are four stages of life:

1. Brahmacharya
2. Grihashtha
3. Vanaprashtha
4. Sannyasa

So, Can one only take Sannyasa after Vanaprashtha or even before Vanaprastha? More precisely I want to know when can one take Sannyasa?

Is there any scriptural guidance about when to take Sannyasa?