Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency care for a sudden “worst-ever” headache, fainting, seizure, new weakness or numbness, confusion, trouble speaking, severe chest pain, or severe difficulty breathing.
Contact a clinician promptly for fever with side or back pain, painful urination, persistent visible blood in the urine, blood clots in the urine, sudden severe flank pain, repeated vomiting, or a major decrease in urine output.
These symptoms may reflect infection, bleeding, a stone, or urinary blockage.
Routine follow-up may involve a primary care clinician, nephrologist, or both.
A nephrologist is a doctor who specializes in kidney disease.
The timing of visits depends on blood pressure, symptoms, kidney function, progression risk, and treatment.
These are not routine follow-up concerns.
The article also says
Monitoring may include:
Blood pressure checks
Creatinine, eGFR, electrolytes, and urine testing
Review of pain, infections, stones, and blood in the urine
Review of medicines, supplements, and possible kidney side effects
Imaging when it is likely to change risk assessment or treatment
Counseling about pregnancy, family testing, or genetic testing when relevant
Every sign above is quoted from the sofidex article on Autosomal dominant polycystic kidney disease. If you are not sure, err upward — it is always reasonable to be checked.