Purchasing "Timed Practice"
I want to buy "Timed Practice" with some of my lingots, but do I only have to buy it once, or is it a one-time-only deal where I have to buy it each time that I want to do it?
The further you progress without getting comfortable with the current level of difficulty in Timed Practice, the harder it will get. This is because Timed Practice includes all previous sentences, grammar, and conjugation for past lessons. (I made the mistake of waiting until near the end of my tree to buy the timed practice option.)