European trips are frequently under-insured because people assume the reciprocal health card does more than it does. It covers a specific and limited thing.
What the health card actually covers
State healthcare on the same terms as a resident of that country.
That phrasing does the work. It means:
You pay what residents pay, and in several European countries residents pay a substantial share of treatment costs.
Private hospitals are not covered, and in some tourist areas the nearest facility is private.
Repatriation home is not covered at all, and this is the large one — an air ambulance runs into six figures.
Mountain rescue is not covered in several countries.
Carry it, and carry insurance alongside it.
The rescue question
In several Alpine countries, rescue is charged to the individual and can run into thousands.
Alpine club membership — Austrian, German, Swiss, Italian — frequently includes rescue cover across several countries plus hut discounts, and reciprocal agreements mean one membership works widely.
It is often cheaper than adding equivalent cover to a policy, and it is worth pricing for anyone walking or skiing in the Alps.
Winter sports
Usually an add-on rather than included.
Within it, check specifically:
Off-piste skiing, which is commonly excluded entirely, or covered only when accompanied by a qualified guide.
Ski touring and backcountry, which is a separate category again.
Piste closure and equipment, which are separate items.
Helmet requirements, which some policies impose.
Driving
A common misunderstanding.
Travel policies cover you as a person, not the vehicle.
Rental car damage and third-party liability come from the rental agreement or separate excess insurance, not your travel policy.
Check whether your policy covers you as a driver at all — some exclude it — and whether the rental agreement permits cross-border travel and unpaved roads, both commonly restricted.
The activities Europe involves
More than people list when buying.
Hiking above a stated altitude, which the Alps and Pyrenees exceed easily.
Via ferrata, which is frequently classed with climbing.
Canyoning, paragliding, whitewater rafting.
Scooter and motorbike hire in Greece, Italy and Portugal, where the licence category determines whether you have cover at all.
List them honestly at purchase.
Trip length
Many single-trip policies cap at 30 or 60 days, and cover simply stops after that.
Long European trips — a Camino, an Interrail summer, a season — need a policy that covers the actual duration, or an annual multi-trip policy, which also caps individual trip length.
What this cannot tell you
Which product to buy.
Limits, exclusions and prices change continuously and depend on your country of residence and age.
Read the wording for the specific policy, checking medical limit, repatriation, the activity list, and the trip duration cap. Those four decide it.