Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
People who smoke or have other risk factors for lung disease may receive a different follow-up plan.
The article also says
Symptoms should be monitored after treatment begins.
Fever and breathing may improve before the cough and tiredness fully resolve.
A cough or reduced stamina can last for several weeks because lung inflammation takes time to settle.
Contact the treating clinician if symptoms are not improving within the expected period, are getting worse, or return after initial improvement.
The clinician may reconsider the diagnosis, check whether the organism is resistant, review whether medicine has been absorbed and taken as directed, or look for a complication.
A repeat chest X-ray is not needed for every person who recovers as expected.
It may be advised when symptoms persist, the original imaging showed an unusual finding, or there is concern about another lung condition.
Return to work, school, and exercise should be gradual.
Fever should be gone and breathing should be comfortable during basic activities.
Follow any specific public-health guidance if testing confirms influenza, COVID-19, or another infection with isolation recommendations.
Every sign above is quoted from the sofidex article on Atypical pneumonia. If you are not sure, err upward — it is always reasonable to be checked.