MUH POOR arguments aside, what are the stipulations besides length for termination?
You mean what can cause a person to lose their benefits besides receiving them for the maximum length? Basically any time that someone stops meeting the eligibility criteria (an increase in household income, moving to another state, etc).
... Then what's the issue?
What do you propose someone do if they find themselves spending more than twelve months over the course of their life in a minimum wage job that doesn't allow them to afford food or housing or healthcare?