Time management is a huge factor for most poly folk we talk to. How do you find time to nurture all the connections you desire, take care of basic life responsibilities, and spend time nurturing yourself as well? How can you tell when you've hit your limit on connections? Is chronological time the most important factor, or is it emotional "time"?
Oftentimes, when I am working with clients who have been injured on the job, or during an exerting activity, they will share with me that there was a point where they knew they were feeling fatigued, and kept on going, "just to finish up that last little bit". They got tired, they got sloppy, they got hurt. This often seems to hold true for emotional exertion as well. If one relationship is good, and two is great, three MUST be even better, and four will blow your mind! Never mind that you don't have time to spend caring for yourself, and your existing partners are already feeling like they don't get the attention that they desire when you have time to spend.
Learning to stop _before_ you hit the point of being "poly saturated" is a fantastic skill to cultivate! When you are at your maximum capacity, any small to medium sized issue at any point in your circle can overwhelm your limited emotional and chronological flexibility.
Being in relationships with other responsible adults is the first step, assuming you fit that bill yourself! ;) Beyond that, learning how much emotional energy and time you have to share with others is key. Resisting the temptation to add "just one more" when you are feeling relaxed and fulfilled, enjoying active growth in all spheres of your life, makes sense. Allow things to settle into a healthy stable pattern before considering new additions.
This isn't a numbers game. I know people that are just as "poly" with one, or even no partner as the ones with four or more. When you need to break out the white board to diagram connections so that they make sense to _you_, maybe that's too much! You know you're dating too much when: (fill in an answer that makes sense to you here).
Attention K Mart Shoppers: Quality counts! Choose your partners, and how many, with care, because YOU are usually the first one to fall to the side when things get rough, and take others you care for with down with you.