I'm wondering the same thing. Im at the 9 day mark and the starting OG was 1.074. Pulled a sample last night and it's 1.020. Still see a lot of movement in the must and airlock still going at 1 bubble every 1.5 seconds. Thanks for any input.
Shouldn't hurt to add a bit, if you smell any sulfur, (like rotten eggs), which comes from nitrogen deficiency, I would insist on adding some now. IME cider takes longer than beer to ferment out, sometimes 2-3weeks.