One of the things I'm learning to deal with as I get older is trying to determine the difference between the occasional aches and pains that mean little or nothing, and those that warrant a visit to the doctor. I am not a hypochondriac by any means and don't like wasting my doctor's time, but also don't want to ignore symptoms that might mean something. For a layman with little to no medical knowledge, it's a very inexact science.
ER, for all intents and purposes. Part-time income <5% of annual expenditure.