See real action
Helpful signs of progress: you start answering faster, speak longer without stopping, convey your thoughts more accurately, and ask for a question to be repeated less often.
The number of new words is important, but does not in itself prove that you can use them in conversation.
Compare identical tasks
Answer the same question within the same time limit every two weeks. Compare notes for clarity, coherence, and number of pauses.
Don't compare the occasional difficult question with an easy one: this will measure the topic, not the progress.
Record the next step
After each check, choose one growth point. For example, add examples, improve endings, or speak more slowly.
A good progression system doesn't just show you a score, it tells you what to do in the next workout.