Do you lose some strength bars after not playing for a while?
I remember playing Duolingo last year in Italian and I would say 70% of the lessons had full bars and now I return there's only 1 bar for each lesson. I think I also lost some Checkpoints. Did this happen to anyone else too? How do I get them back without redoing the work all over again? :( Mille grazie!
Weird. Here you go:
Duolingo uses spaced repetition; there is a lot of literature on this and if you're interested you can do a Google search and read up on it.
In a nutshell, "spaced repetition" means when you learn something new, you need to review it pretty frequently at first so you don't forget it. Over time, you review it less and less and eventually it moves from short-term memory to long-term memory.
When a skill set loses its gold color, that's Duolingo's way of saying "Hey, it's been a while since you reviewed this skill set, you should look at it again!"
Skills lose their gold color faster if you miss a lot of questions or hover/peek for hints. They keep their gold color longer if you get all the answers right. This is also part of the spaced-repetition method. You review things you don't know more frequently, and things that you do know less frequently. That allows you to focus on things you really need to work on without wasting time on things you already know.
Some people go through the entire course and then go back to turn everything gold. Some people keep the skills gold and do a lot of reviews as they progress through the course. Pick what keeps you motivated.
My personal approach is to review 3 or more lessons before tackling a new one. (A "lesson" being one set of questions inside a skill set). If the review lessons go really well, I do a new lesson. If there was any confusion in the reviews, I review more until the confusion is gone. My progress is very slow but I'm a "slow and steady" type learner. Most people finish their courses a lot quicker than I do.