I try so hard to keep up with all the lessons - I have reached the 49% fluency mark. But just when I get to the point that I am up to date I go back into the system and find that I have fallen right back and I have to redo so many of the lessons!!!! I find this frustrating . . . .
It's just not necessary to keep everything golden. Just keep moving at a comfortable pace and revise when you feel up to it. Really, you'll probably do better in the end because frustration is not an easy master. Duo is created for people to work at their own pace and with the intention of keeping the learner motivated but not frustrated.
That's what I've done all along and you can see how many languages I've done and to what level. But you are the one to decide when and how much to do.
It's nice to have everything gold, but just don't get fustrated- one reason why you get fustrated is probably because everything gets another colour, not gold, but to make this gold all the time is just practice and practice- don't think about getting high fluency or getting to the end. When you can do a skill very good, you can strengthen it- and in all the other skills with the words of that skill, do those words right. Try remembering words of the skills you are practicing! (Fluency is NOT important at all)
My main goal is learning, not to get everything golden. Reaching the 49% fluency is also a very good job, just think about the best way you can learn by doing your exercises.