"Strengthen skills" only tests first five lessons?
When visiting the practice/strengthen skills page (https://www.duolingo.com/practice), only the first five lessons have been, and are, tested. Is this deliberate? Is there a way I can test all previously finished lessons?
The strengthen skills works by spaced repetition and so it's less likely to give you your more recent skills because it knows you've seen them more recently. But because the algorithm doesn't actually look at the words you've seen recently, this can get really funky: I see "flickan" and "pojken" in nearly every lesson but they still show up on strengthen skills frequently because that unit was a long time ago.
So when I really want to practice specific weak spots, I go to those lessons specifically. It does take more time, but practicing more isn't a bad thing unless you're crunched for time.
As you progress up the tree, you may find that the strengthen skills is more and more useful: in Spanish, I almost always get something that really deserves my full review.
Oh, I see what you're saying now. Yeah, that does seem more extreme than what I've seen, though it took until today for a skill of mine to ungold. (I do a lot of review.) I did two strengthenings and got words from the first few skills including the one that was weak, but not enough of the weakened skill to gild it again.
I've read from some really in-depth explanations that this might be the result of poor naming choice: in order to actually regild your skills, you need to practice specific words, but the strengthening algorithm doesn't look at words. However, that doesn't explain why you're several rows down the tree and still only ever getting words from the first skills.
Many have raised this issue - it seems to be across the board. I've tried everything to get it to give me different/broader range of words, nothing seems to work. Occasionally I get a random word outside of the basics. It's frustrating - because it's such a potentially useful tool for revision.