Generally I like to set a new cards/day goal (usually around 30 new cards per day if I want to spend rouuuughly 30 minutes per day studying), and then I make new cards as often as I need to in order to constantly have a daily supply of cards.
For me, the card creation seems to average around 1 minute per new card, so I could theoretically do:
- 30 minutes of reviews every day, and 30 minutes of card creation every day.
- 30 minutes of reviews every day, and 60 minutes of card creation 3-4 times per week (This is what I'm doing for Spanish right now)
- 30 minutes of reviews/day, and 90 minutes of card creation 2-3 times per week, etc.
When I learned French, I had a tendency to do 3-6 hours of card creation on Sundays, and then study those cards for 1-2 weeks, then repeat. Nowadays, I kind of prefer shorter, more frequent bursts of card creation. I think it works slightly better, since there's less of a delay between when I create a card and when I review it. It gives me less time to forget.