How frequently do angels incarnate to live a life as a physical human, and for what purposes?

This is more common than you might think although it is not a significant percentage, being in the neighborhood of 1 in 1000. That is still a lot of angels walking around as human beings. The reason for this is the dire circumstances humanity is facing. The fact that humans at this point are truly coming from behind and with the huge karmic backlog faced by the average person, it is harder than ever for the divine realm to have an impact on things and enlist people to serve the light through inner inspiration as reminders of their life purpose, prior doings, and destiny as a light-bringer. Many become sidelined and never participate in a meaningful way to improve things while they are here and, in effect, it is a somewhat wasted opportunity. There needs to be a sizeable body of humans working on the same goal, in alignment, and mindful of the task at hand. The current human condition is not allowing that to happen readily. This is the hill you are climbing. We will continue to help and support you but this is a major aspect of what is going on right now and will govern the fate of humanity in the end. Anything that can help is a bonus, and so we are essentially allowing what we consider a very sizeable angelic complement to infiltrate the human community as helpers and healers to give that much extra support so people have someone they can count on in their corner who will be dedicated to them and work on their behalf and will be tapped in enough to know what is needed to happen to benefit their target human. And it is always very much a blessing because the relationship whether as caretaker, friend, mentor or silent healer, will be pivotal in moving the person forward. This creates less overall burden for the light and helps keep people more at par with one another and not falling too far behind. Having too many deeply troubled individuals in their midst who pose a burden and are seemingly refractory to change and attempts to help them, is a further encouragement for the darkness and a discouragement for the human community. This can be a true godsend in a very practical sense because an angel at your side can be just what is needed to get people over the hump, so to speak, to make significant healing strides when coming from behind in a serious level of deficiency.