Valid park ticket and MagicBand or Key to the World Card required. Guests without the Park Hopper Option or Park Hopper Plus Option must spend the day at the same park where they’d like to enjoy the Extra Magic Hours benefit.
Whether Extra Magic Hours are worth attending is the subject of regular debates.
You get to enter early or stay late but so do many more guests. Walt Disney World has over 30,000 hotel rooms and each will hold several guests. All these guests can also attend during EMH. That is lot of extra guests!
If you intend to get to the park early for morning EMH they are probably worth attending. However, if you are going to miss opening it is worth going elsewhere.
In the evening EMH are busier the earlier they are held. If a park’s EMH are to 1am they will be quieter than if they are to 11. In addition they will usually quieten in the last hour. However; they can be very busy and the most popular attractions might have very long waits.
Avoid the park with EMH it will be busier. Attend one of the other parks.
If you are staying offsite plan to avoid the parks with EMH. The only exception to this rule is if entertainment is only held on this day.