How do you decide if you are ready for the Three Passes trek?

The Three Passes trek in Nepal's Everest region crosses Kongma La, Cho La and Renjo La in a single loop. People often describe it as a step up from the Everest Base Camp trek, with longer days, more time at altitude and fewer places to turn back. Some trekkers do it as a first Himalayan trek. Others wait until they have a few shorter treks behind them.

If you have done it, or are planning it, how did you judge your readiness? Did you rely on a training plan, earlier altitude experience, or advice from a guide? Was there a point where you changed your plan, such as adding a rest day, dropping a pass or reversing the route?

I am also curious about the practical side. Which pass did you find hardest, and what made it so? How did weather or season affect the crossing? If you went without a guide, would you do it that way again?

Share what worked, what you would change, and what you wish someone had told you before you left.