Well, it’s up to you in the end, but I might suggest starting with the N5 deck, and order it by something like Anime, or Novels, or whatever ordering suits your interests.
With N5, presumably you’ll be prompted to learn several Vocabs that you ‘already know’. There are a few different ways to handle this:
- Just Learn them from scratch anyway, with the benefit that you get to see these familiar words being used in natural context sentences. Also, if you already know them well, it takes a lot less effort to answer them and advance them up the SRS levels.
- For ones you really know well, you can use the Mark As Mastered button to advance them immediately to SRS level 12, Mastered, so you’re basically skipping any N5s that you really don’t want to study again.
- A compromise between (1) and (2), you can specifically set the SRS level of any N5 Vocabs, based on how confident you are with it. E.g. If you’re 90% confident with a Vocab, you could set its SRS level to something like 9 or 10, so that they won’t come up for weeks or months, and you’ll only have to answer them correctly a couple of times.
Personally, I decided I wanted to experience the whole Bunpro Vocab experience from scratch, so I started from scratch on N5 and just zipped through them. Along the way, I did find some good words that I had not been exposed to before, especially kana-only words that happen to be quite common in written Japanese.
Then I zipped pretty quick through N4, but again picking up some useful words along the way. Finishing off N4 started to get a bit challenging (in a good way), since they were less common words, but were still N4 words.
Then I started N3, and while the first bunch of words were pretty easy because they were pretty common words, once I got about midway through N3 I ‘found my place’, and had to slow down on Vocab significantly, and start pacing myself as usual.
So, I’m currently working at finishing off N3, but I’ve also been adding a lot of extra words (N2, N1, and even some of the A decks and the E1 deck) that I just happen to run across or be interested in.
But, may main point is that starting from N5 isn’t really a bad idea, IMHO. Of course, it depends on your own judgment and goals. It’s just what I ended up doing, and I felt it was worthwhile of my time. Cheers!