'Marriages are arranged in heaven' is an old saying. If this is true then is there any need to match the horoscopes before proceeding for the marriage. Yes, it is almost necessary because ancient saints by virtue of their knowledge have found out the factors responsible for disturbances in a married life which otherwise ought to be smooth. They have also revealed the remedial measures to bring the train back on the track.
Whenever, we go to astrologer for matching the horoscope of marriageable boy and girl, we simply ask him to confirm about the number of points (gunas) available in the horoscope of both. When the number exceeds more than 18 out of a total of 36, we become sure that matching is satisfactory. More the numbers more the satisfaction. We do not go beyond that except the Manglik Dosh. Even most of the astrologers generally approve this theory and nod for the marriage. But practically, this is not the only criteria for a successful marriage, I my self have seen the lack of harmony and availability of disturbance in married life of couples who have scored 28 or 32 gunas out of 36. They or their parents raise fingers on the sanctity of the ancient art of astrology. So, whenever marriage is considered, the natal charts of the would-be bride and groom should be thoroughly evaluated for a happy married life. Now let us start from the importance of Gunas.
While matching gunas we consider Ashtakut Guna Milan (as per Indian astrology) the details of which are given in the following chart: