There are a lot of advantages to having a partner who is the same type you are. You have an instinctive understanding of each other's thinking and ways of doing things. You are likely to have similar priorities. If you also share the same values, you are likely to get along uncommonly well. This kind of relationship is generally as easy to slip into as bath water, unlike the brisk awakening which comes from a relationship of opposites.

The difficulties come in several areas. One is competition, with each partner trying to outdo the other in terms of their type's outstanding characteristics. For example, two Artisan Promoters (ESTP) might compete to each be more outrageous, daring, and conning than the other. Two Rational Architects (INTP) can easily have fights over who the true expert is in a particular area. And two Idealist Teachers (ENFJ) may end up with two teachers and no students. Reg and Linda are both Rational Fieldmarshals (ENTJ). Both are certain that their ideas are right. They regularly have loud, animated arguments as the debate the merits of each idea. When they agree, it is impossible to convince them that there might be a flaw in their logic.

Another difficulty is that both partners have similar strengths and weaknesses. Neither will have skill in a number of common weaknesses, causing potential battles over who has to do the jobs neither has skill in. Two Rational Inventors (ENTP) are very likely to end up in a filthy house with many things broken since neither likes to do maintenance. Two Guardian Protectors (ISFJ) will probably get taken advantage of regularly since confrontation is a weak area. Two Idealist Healers (INFP) will have a hard time deciding which are the relevant facts in making decisions, and two Artisan Performers (ESFP) might find it difficult to settle down as they jump from one thing to the next. John and Bernice, both INFP agonized over every decision they made. They found it much easier to make decisions when circumstances forced a choice. For example, they got married when they found out Bernice was pregnant. Their children just happened. Deciding on schooling for the kids caused extreme stress, but, eventually, they became more confident in their choices.

The third area is potentially the most dangerous, especially if the couple has children. Having the same personality type can cause constant reinforcement of some of the worst characteristics of that type. As an example, two Guardian Supervisors (ESTJ) are likely to encourage one another to set strict rules and to judge infractions harshly, something that is likely to cause many problems with others, especially children who are not Guardians. Two Artisan Composers (ISFP) can become ultra flaky. When one finally decides on something, the other is likely to play the "we don't have all the information yet" card. Two Idealist Champions (ENFP) are likely to create a chaotic, emotional environment which can wreak havoc on children needing structure and emotional boundaries. Two Rational Masterminds (INTJ) may create a sterile environment, practically devoid of human emotion or touch.

A pairing where both partners are the same type works best when they are aware of the potential pitfalls and work to overcome them. Also, it is very helpful if they have strong skills in another temperament. Brent and Lydia are both Guardian Providers (ESFJ). Brent feels almost as comfortable as an Artisan as he does a Guardian and enjoys weekends with buddies testing the limits of their toys. Lydia was raised in a family of Rationals and Idealists and learned to value the power of the mind and belief in people. Together, they do a fantastic job of entertaining and actually have their own successful party planning business. They have a daughter who is probably a Rational. Lydia understands that she needs time to herself, but she can't understand why the girl is so awkward socially and doesn't even care. Lydia's dad has told her to leave the girl alone, she's just like he was.