Health sharing members must typically commit to a healthy lifestyle in order to be admitted. Even so, there are no restrictions on pre-existing conditions, so individuals can join regardless of their health history. There is also no lifetime cap on payments, and no requirement to see doctors who are in a particular network.
The health-sharing exemption is authorized by the Affordable Care Act, so members who join one of these programs will not face a penalty for being uninsured. Exactly how members will report their membership to the IRS is not known at this time, as this information will likely not be available until 2015.