Travel Insurance Worth Buying: A Plain-English Checklist
Travel insurance is cheap until you need it. The difference between a useful policy and a useless one is usually in the exclusions, not the price.
Travel insurance is one of the few purchases where the cheapest option can be actively harmful. A policy that costs $15 and excludes the activities you are doing, or caps medical evacuation at $10,000, is not insurance. It is a document.
The good news is that a useful policy does not need to be expensive. It needs to match the trip. A city break and a trekking holiday have different risks, and the policy should reflect that.
What you actually need
Prioritise medical cover, emergency evacuation and repatriation. These are the costs that can bankrupt a traveller. A broken leg in a remote area can cost tens of thousands of dollars to stabilise and transport. Check the limits in writing, not the summary table.
Then add cancellation cover, baggage cover and travel delay cover if they matter to you. Cancellation is often the most-used benefit, but it is also the most tightly defined. Baggage cover is usually capped at a low amount and subject to depreciation; it is not a substitute for insuring expensive equipment separately.

The exclusions that matter
Common exclusions include pre-existing medical conditions, extreme sports, alcohol-related incidents, travel against government advice, and claims caused by not following local laws. Adventure activities are often excluded unless you buy an add-on. Check the definition of adventure: some policies exclude hiking above 3,000 metres or any activity involving ropes.
Also check the excess. A $100 excess on a $150 baggage claim means the cover is largely symbolic. For medical claims, the excess matters less than the limit and the evacuation terms.
Medical cover and evacuation
Look for a medical limit of at least $100,000 for short trips, and higher for remote destinations. Emergency evacuation should cover transport to an appropriate facility, not just the nearest clinic. If you are trekking, check whether helicopter evacuation is included and who authorises it.
Confirm that the policy covers treatment in the country you are visiting and that direct billing is available where possible. If you must pay upfront and claim later, keep every receipt and medical report.
Buy insurance for the event you cannot afford, not the event you can. That means medical evacuation first.

Cancellation cover
Cancellation cover reimburses prepaid, non-refundable costs if you cancel for a covered reason. Covered reasons are usually narrow: serious illness, a death in the family, jury duty, or a documented transport strike. Change of mind is not covered.
Check whether the policy covers the full value of your trip and whether it includes supplier insolvency. If you book expensive flights or tours, the cancellation limit should match the amount at risk. Keep receipts and booking confirmations; claims without documentation are usually rejected.

How to buy well
Buy from a provider regulated in your home country. Read the product disclosure document, not just the marketing page. Compare at least three policies on medical limit, evacuation limit, activity cover, excess and cancellation terms.
Declare pre-existing conditions honestly. An undisclosed condition can void the whole policy. If you are unsure whether an activity is covered, ask the insurer in writing and keep the reply.

The bottom line
Buy insurance for the risks you cannot absorb: medical care, evacuation and a cancelled trip. Read the exclusions, declare your conditions, and match the policy to the trip. A good policy is boring, specific and easy to claim on.