For those visiting Machu Picchu from January 2019 onward it is good to keep in mind the latest changes made to the entrance tickets to Machu Picchu and times for visits.
In recent years Machu Picchu was suffering from huge lines at the bus station to take the 30 minute bus journey over the Hiram Bingham road between Aguas Calientes and the actual entrance of Machu Picchu. In high season the waiting time could be up to three hours in the morning, something that is unacceptable.
The INC (the governing body for Machu Picchu) therefore looked for solutions and found a possible one in coordinating entrance times with a maximum allowed permanence and coordinate this with the bus departures. The new entrance times are every hour from 6.00am till 2.00pm and you are allowed to spend maximum 4 hours onsite. There are approximately 600 spaces available for all time slots. Prices are the same but there are voices saying that next year prices for the afternoon tickets may become cheaper to stimulate afternoon visits.
For those looking to hike Huayna Picchu or Machu Picchu Mountain keep in mind that the Machu Picchu Mountain and Huayna Picchu entrance rules also slightly changed. There are now 3 slots for each of these two possible hikes. You can enter the site at 6.00am to start the 7.00am Huayna Picchu hike, enter at 7.00am for the 7.00am Huayna Picchu slot or enter at 8.00am for the 10.00am Huayna Picchu slot. Keep in mind that with this last one you will most likely be guided towards the exit upon coming down from Machu Picchu. For Machu Picchu Mountain this is the same except that the second climbing time you enter the site at 8.00am for the 9.00am Machu Picchu Mountain climbing slot.
These are the most important new Machu Picchu regulations. The other change is that you now officially - it seems that this has not yet been implemented- need to be accompanied by official Machu Picchu guides for your first visit to the site. If you would re-enter later that day or the next day you would no longer need the guide. You can also only leave the site and re-enter (bathrooms are outside the actual Inca citadel) if you are still within the time slot you have the entrance ticket for Machu Picchu for.