There are two options - do it in a day or take several days. I have done both. Last time, due to the convoluted lottery system, I did it in a day. The advantage is you only need a day pack which serves to speed up the hike. Less weight equals greater speed. The downside is the hike is faster and it is difficult to enjoy the lakes and stream.
Most important, on a day hike there is less time to acclimate to the elevation. Either way do plan to camp at Whitney Portal and take the time to have pancakes at the cafe. If you plan to do it in a day use a headlamp and start at 2 or 3 in the morning. It will take longer to reach the top than you plan.
Savor the hike. Speed is important but take your time and enjoy the bucket list experience.
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