While every medical decision should be made in context with the severity of disease, other medical conditions, personal preference and other factors that make a person "whole", I almost always recommend surgery for primary hyperparathyroidism. The risks of surgery are extremely low and the benefits can be huge. There is no patient who is "too old" for surgery.
Fortunately, most people who have PHP are without major symptoms or disease. We often diagnose the disease in its early stages before major problems have occurred. However, if the disease is left untreated then we will all develop symptoms in time. The most common issues we aim to prevent are weak bones (osteopenia & osteoporosis) and kidney issues (stones and failure). Anxiety, depression, memory "fog" or loss, fatigue, abdominal pain, nausea, constipation (and sometimes diarrhea), joint pain, bone pain and muscle aches are among the most common symptoms people experience.
As there are no medications to treat PHP, I advocate for surgery early. Not just because I'm a surgeon, but because I would recommend it for my family. If the surgery is performed by an experienced parathyroid surgeon the risks are extremely low (less than 1%) while the benefit can be significant. The incision size is quite small and the recovery is quick. Most people only take one or two pain pills after surgery as Tylenol is often enough to cover any discomfort.
Many medical doctors follow an antiquated set of criteria as to when to refer patients to surgery for primary hyperparathyroidism. This isn't intentional ignorance or negligence. If those doctors trained in areas without access to excellent parathyroid surgeons the risks did not outweigh the benefit. Again, in the USA, that scenario isn't the reality we live in. Restricting surgery to those younger than age 50, calcium levels 1 above normal, and kidney or bone disease just doesn't make sense anymore as there are excellent parathyroid surgeons in nearly every state. Why wait until you have a potentially permanent side effect of uncontrolled primary hyperparathyroidism?