Yes, agree, for the more quirky grammar rules you need to go elsewhere! Btw, you can click on the heart button top right to get more lives just by practicing - then running out of lives stops being an issue.

I just use the free version. And when I inevitably lose all my lives, just "practice" to get them back.

I do. It has helped me. I've been doing other things too, but 20 mins every day on duolingo keeps you in the zone, and increases your vocab and understanding.