Kevin's Method

A0

A0 - A2

B1 - B2

This is where Unutma really shines. You've entered an awkward middle-ground between having some automatic intuition about grammar, have a foundation of vocabulary from your early A0-A2 days and suddenly your biggest limiting factor is that there are THOUSANDS of commonly used words which you have not been exposed to yet. The closer you get to C1, the less that you should rely on Unutma, and the more that you should be learning through immersion (books, radio, tv, movies, speaking with natives). Some heroic learners jump straight into reading and looking up every word that they don't know which at the beginning is basically all of them. I've found the progression to be much smoother by learning the 2,500 to 10,000 words I haven't learned yet with Unutma, before being able to sit down and enjoy literature at a respectable pace.

C1+

By this point, you can speak your target language totally fluently and will easily learn new vocabulary, fine details of grammar, rule exceptions, etc. without help from any apps. Time to start the cycle again with a new language :)