Each language has a slightly different number of total days worth of material. You can find that
number by going to your deck browser (Click "Browse" on the top of the first window in Anki),
choosing the "Spelling Rules and Example Words" sub-deck (On the left side, around 11-15 items
down. You may need to click on an arrow to expand the sub-decks), and seeing how many cards
are in there (on the top of the screen).
You move through those cards at a rate of 20 new cards/day. Spanish, for instance, has 408 cards
there, and will take 408/20 = 20.4 days to complete. Roughly, the last four days of study are just
extra example words, so you'd be done with the Spanish spelling rules in about 16 days, and finish
out the last of the example words by day 21.
Naturally, if you crank up the New Cards/Day number, then you'll go through the cards faster. If
you do that, we'd suggest doubling your numbers (56/40/16 new cards per day, instead of