Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
New chest pain, fainting, severe shortness of breath, confusion, or uncontrolled bleeding requires emergency care rather than waiting for a scheduled appointment.
Follow-up usually includes another CBC to confirm that hemoglobin is improving.
Depending on the cause, a clinician may also repeat a reticulocyte count, ferritin, iron studies, vitamin levels, or kidney tests.
The timing varies with the severity of anemia and the treatment used.
Routine follow-up is appropriate when symptoms are stable and a treatment plan is in place.
The article also says
Improvement in symptoms and hemoglobin does not always mean that treatment is complete.
Iron stores may take longer to rebuild than the blood count.
Continue treatment for the period recommended by the treating clinician rather than stopping as soon as you feel better.
Contact your healthcare team if symptoms do not improve, side effects prevent you from taking treatment, or bleeding continues.
Recurrent anemia may mean that the original cause remains active, treatment was not fully absorbed, or more than one condition is present.
Every sign above is quoted from the sofidex article on Anemia. If you are not sure, err upward — it is always reasonable to be checked.