Thus, it's not required that everyone has partners, but it's certainly a good idea, as seen above. Even the apostle Paul rarely traveled alone, but tried to stay with other Christians, as noted above. But, in our fallenness, there are many times when a friend seems more real, more present, less ignorable than God. Beyond the initial asking for prayers and support, those accountable to each other should be able to reach the other at just about any time for any reason. A friend that you know, and have trusted with the rights to bug you at any time over your walk with God, can help spur on the righteousness we desire.
Accountability is a less strict relationship than discipleship, which has some similar traits.
You do not necessarily need to be accountable to only one person, but you may be in a small group, or several small groups. Neither side has the easy task in those commandments, but both must work to continually serve the other. Until we are able to walk with Jesus in heaven, our weak states here on Earth need help, support, and accountability to others. This is the 3rd access this week, and the 426th access since April 13th, 1999.