Mental Compatibility
What is the basic mentality of two people; are they intellectually inclined, or more inclined towards family matters; towards social service. Two people could also be quite business minded, and would tend to give money high importance. Some people are basic fighters, whether the situation is social or political. Therefore a match between a person who has an inclination towards social service will find it difficult to get along with a person who gives money high importance.A balance between the type of mentality between a man and a woman is necessary. As a woman is traditionally a caretaker of the family, it is always better if she is seen as being more inclined towards family. This also ensures that ego problems are minimised between two people.
 

Power Compatibility
In a relationship a power struggle is often one of the biggest problems. When both man and woman try to be boss of the family unit. If there is continous struggle for power, problems will be many. It is important that the man be head of the family and while a woman can be equal to a man, and this is considered ideal, when a woman has a personality that is more powerful, problems will arise.
 

Longevity of life with one another
It is important for the long term happiness of two individuals and their family that they are blessed with a long life, and a long married life, so that companionship lasts a life time and the presence of both mother and father is essential for children. Moreover it ensures that no financial or emotional instability comes into married life due to the loss of a partner or the ill health of either one. This point ensures that two people will live a long and healthy life with one another.
 

Physical habits and its relation sexual compatibility
Every person has a physical nature that is characteristic of that person….some of us are inclined to enjoy cool weather and the outdoors, while some of us are very indoor people and like to be cosy. Some are very adventuourous while some are quite lazy and laid back. If two people have two completely opposite physical characteristics in their personalities, they will find it difficult in the long run to have a sexually compatible relationship. While this is not apparent to many initially in a relationship; but over a course of time, these differences become more prominent.
 

Adjustment and affection
This point reflects the amount of adjustment two people will be willing to do for one another in their marriage. This also reflects the affection which is between two people towards one another, naturally when there is a high level of affection then a will to adjust also exists. It reflects the interactions of day to day behaviour and basic likes and dislikes, and type of lifestyle that each enjoy.
 

Comptability at a spiritual level
What type of personality do both people have, are they spiritually inclined and tend to be givers and are also nature lovers, the second type are balanced and tend to be both givers and takers in life, the third type are takers, and tend to be quite aggressive and selfish. It is important that a balance exist in the relationship for it to be successful.
 

Success and prosperity
This is considered to be one of the most critical in the success of a marriage. Do the charts of both people enhance the prosperity and well being of the family. Will there be family happiness both with one another and with children. The well being of the family as a unit is relfected in this point.
 

Healthy children
Children are a vital part of most marriages, and their good health is most important for family happiness. Ancient vedic astrology recognised the importance of genetic compatability and takes into account any hereditary problems that could possibly occur due to marriage. This is an important point for those who wish to have a family; however in light of medical progress this point is not as important as it used to be. Nonetheless, if there is a problem indicated at the outset of marriage, one can always check before taking any decision.

There are further aspects that are studied in Vedic astrology which shed light on further aspects, but the above forms the basis of ascertaining whether a relationship will be successful or not.

Better to be safe than sorry!