I don't know if it is just me, but my tree fades SO fast. How often do yo guys need to strengthen a skill?
I have 1-3 skills that need to be re-gilded daily. Some people claim that their tree degilds much slower if they constantly "Strengthen weak words".
All the time - in fact, all I do is strengthening exercises. I finished the tree in September and am still working to get it completely gold. I do 2-3 strengthens a day (in the Esperanto tree). I find it frustrating, but I'm also somewhat OK with it because I haven't learned (remembered) every word in the course yet. Nowadays I only do strengthening via Timed Practice and only with chosen lessons (so not the general Strengthen weak words).
Well, I had to do 6-9 lessons per day to stay gold. But I will not do that any more. After finishing Nature I went through Ideas and after finishing it (both without an error) Nature is not gold any more. Comparing Esperanto sentences with German ones, they are much longer and Duo is very rigid and throws me away if I type 'everyting' or other typo. I am going to spend my time on something more useful.