With the new Crown System, and spending hours at it, it seems I'll need 100 years to reach Level 5.
My Spanish tree has 500 lessons in 108 skills. (I'm testing the new Spanish tree, so you may have fewer lessons and skills in your Spanish course.) If a skill that has N lessons takes N x 12 finished lessons to get 5 crowns for that skill, then the entire tree would take 500 * 12 = 6000 finished lessons.
At 6 lessons per day, it would take 6000/6 = 1000 days, or a little less than 3 years, to get all 108 * 5 = 540 crowns starting from nothing.
Since you are already at level 23 in Spanish, you probably already have 200 or so crowns, so it will take less. If you're at level 2 for everything, and have 108 * 2 = 216 crowns, you already have credit for 500 * 2 = 1000 finished lessons, so it would take about 1000/6 = 167 days = 5.4 months less.
It's by design that it takes so long to get all the crowns. Since you're at level 23 now, you've probably been in a boring rut of review for quite a while. Now you have a new long-term challenge.
It's not linear; it's a Fibonacci sequence: 1, 1, 2, 3, 5. See "https://en.wikipedia.org/wiki/Fibonacci_number".
If you did each lesson exactly once, you'd get from nothing to 1 crown per skill. If you did each lesson one more time, you'd get from 1 to 2 crowns per skill. Then it takes 2 more times per lesson to get from 2 to 3, 3 more times to get from 3 to 4 and finally 5 more times to get from 4 to 5.
A very funny observation, thanks. But the crowns "improvement" issue seems to have rattled a lot of cages. And different issues with different platforms. I guess the different teams need similar targets for different levels, but that seems not to be the case (from the discussion boards I am idly looking at)
My answer here https://forum.duolingo.com/comment/27210399
Du scheinst Dich auf die Skills weiter oben im Baum zu fokussieren.
The better strategy might be to work from back to top and strictly focus on the 17-20 quite difficult grammar skills called "Verbs:" (maybe leaving out Present1-2).
This is the strategy which I will be using for my own for my EN-PT (forward) tree.
What do you and others think?
Do you do the SP-DE reverse tree?