There is a pathway to getting a new lesson:
||1w 3d 9h
||3w 3d 8h
||7w 5d 7h
||24w 6d 6h
When you learn a new item (radical, kanji), you will be tested on it four hours later, eight hours later, one day later, two days later.
During the first three review steps, your item is marked as “apprentice”.
After the “two days later” (fourth) step review, a correct review changes the item to “guru”.
When an item is “guru”, you are considered to have learnt it well enough to receive new lessons based on that item. New kanji or vocabulary (words and phrases) based on that “guru” item then become unlocked.
If you make an error during a review, you will go back two steps, except when you are in one of the apprentice steps, where you go back one step.
After a radical (blue background) item becomes “guru”, any kanji which is derived from that radical becomes available to you as a new lesson. After a kanji (pink background) item becomes “guru”, any vocabulary (purple background) derived from that kanji will be unlocked.
After 90% of a level’s kanji items become “guru”, you go up to the next level. Many people call this “levelling up”. Any vocabulary related to the recently guru-ed kanji becomes available. A new slew of radicals and kanji (for the next level) also become available.
Every day, someone posts a new thread about this issue or they complain it is too slow and not worth using.
As the number of guru’ed items pile up, you will eventually feel very differently about the workload. For example: one guru’ed kanji can result in three new words / phrases. Each level has 30 or more kanji. If you stick with the system, you will get busy.