The trek you regret is almost always the one you were not honest with yourself about. Difficulty ratings on trek listing sites are notoriously inconsistent — one operator's Moderate is another's Challenging.
The Four Honest Questions
1. How many consecutive hours can you walk on flat terrain right now?
Not after six weeks of training — right now. Under four hours: start Easy. Four to six hours: Moderate. Six to eight hours with hills: Difficult. Eight-plus hours with loaded pack and elevation: Extreme.
2. Have you spent a night above 3,000m before?
Altitude affects people unpredictably regardless of fitness. If you have never been above 3,000m, add one difficulty tier of caution to any trek that spends multiple nights at that altitude.
3. What is your pack weight experience?
A 10kg loaded daypack changes the calculation for every question above. If you have never trained with a weighted pack, subtract one difficulty tier from your assessment.
4. What is your mental tolerance for discomfort?
Physical difficulty and mental difficulty are different things. A person with high discomfort tolerance may find Difficult treks energising. Know which one you are.
Reading Difficulty Labels Accurately
When comparing treks across operators, ignore the label and look at the data: maximum altitude gained per day, daily walking hours, terrain type, and distance from emergency medical facilities.
A Practical Test
The single best predictor of trek readiness is a day hike with your actual gear. Find a local trail with 600-800m of elevation gain and do it at a steady pace with your loaded pack. If you complete it comfortably and recover within 24 hours, you are ready for a Moderate multi-day trek.
The goal is not to conquer the mountain. The goal is to return from it and want to go again.