Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe difficulty breathing, blue or gray lips or face, new confusion, fainting, severe or persistent chest pain, or coughing up a large amount of blood.
And for anyone, someone who:
Contact a clinician sooner if symptoms improve and then become worse, fever develops after being absent, or wheezing and breathlessness continue.
Parents should also seek medical advice promptly for infants or for children who are breathing harder than usual, drinking poorly, or behaving unusually.
Seek prompt, same-day medical care for:
And for anyone, someone who:
Routine follow-up is reasonable if the cough is not clearly improving after about three weeks, continues beyond several weeks, or repeatedly returns.
For routine recovery, reduce exposure to others while feverish or acutely unwell, cover coughs, wash hands, and follow current public health advice if COVID-19 or influenza is suspected.
Staying up to date with recommended vaccines can reduce the risk of some infections that cause acute cough.
The article also says
People who are pregnant, immunocompromised, older and frail, or living with serious heart or lung disease may need earlier assessment.
Every sign above is quoted from the sofidex article on Acute bronchitis. If you are not sure, err upward — it is always reasonable to be checked.