One of everyone's biggest nightmares is losing data.
It seems like I ritualistically deal with this every 6 years when my external drive fails, and then I have to get the whole history back (expensively).
I have been using Duolingo for almost 3 years to learn a language, but I don't know anything at all.
Of course, I have some basic vocabulary from the vocabulary words, but it's not conversational level. I'm currently considering buying textbooks and workbooks.