Originally Posted by GUWonder

For ORD GE enrollment on arrival, renewal and initial GE applicants are handled at the same area — as is common at relevant airports for enrollment on arrival — and the length of the wait in terms of number of applicants and time for applicants to be processed can vary. And at ORD too — especially if having to make a relatively tight connection for flights departing from Terminals 1/2/3 — the lines for enrollment on arrival may be such that a GE renewal applicant able to use GE may want to skip the enrollment on arrival service and do it on a different day. ORD used to have very limited hours for enrollment on arrival but they seem to be doing enrollment on arrival over longer hours than used to be applicable.