Also @Gakushuusha . Remember that your reviews are timed according to the level after apprentice as well which means they come in big batchs if you just do too much lessons at a time especially if they advance to Guru at the same time. In the beginning you don’t feel it much but later on it is a big impact as they pile up. I had days with more than 200 and it is not fun. I have been doing 10 to 15 lessons a day an the reviews number stay around 120.
This post has some good info on how wanikani works and a lot of tips from someone that already reached level 60.