With some rare exceptions, you always make a card. When you find a new word, without a card you can't be sure that you won't forget it the second you close a dictionary.
If you create a card, it doesn't mean you have to learn it. I have new cards per day set to 0 and learn the cards I select manually from my sentence bank. Whether to learn the mined card depends on your current level. Beginners should focus on learning common words. There are various tips to achieve that.
- Using frequency lists. Frequency lists are not perfect, but they give you a rough idea of how useful a word is. Don't mine the word if it has no frequency data. If the word is found in a frequency list, mine it. If you want to be strict, mine a word if its frequency is high enough.
- Learning only the words that you have encountered at least once before but haven't memorized. When you see an unknown word, check if you already have it in your Anki deck. If you have a card, but the card is still new, learn it now.
As you progress, these tips help less and less.
Frequency lists become inaccurate very fast. You need more specific lists.
After just the first ~1000 words on a list, the frequency of the words begins to vary significantly depending on the specific sources from which the list was created. If a word has high frequency according to a list, you might still rarely see it in your immersion.
Words you learn are not common anymore, and it takes a long time to encounter each word twice. Some words come up maybe once or twice a year.
Making cards doesn't take as much effort as it used to in 2010, so it's easy to make a card just in case even if you won't need it. With Rikaitan you can press the + button and continue reading. In GoldenDict you can use the context menu and click "send to Anki". In mpv with mpvacious you press Ctrl+N.
Advanced learners definitely don't need any excuses to make a card. In my experience, after reaching a certain point I quickly stopped caring about frequency lists or anything else. I started mining everything that simply looked interesting.
If you're feeling lazy then just don't mine, as long as it's not your permanent state. Immersion learning is not math, you're not going to get a bad grade if you don't learn something. If the word is important, it will come up again.
The "always make a card" approach is better than having to decide every time. It comes with only two downsides.
- You have to clean your Anki collection from cards that proved to be unnecessary.
To do that, you can filter new notes by their creation date.
For example, type
is:new -added:365to see cards that were added more than one year ago but haven't been learned.
- If you're a beginner, having to save everything could be too tedious. When there's a new word in every sentence, no technology can help you overcome the initial struggle. If you are stuck and don't want to pause your immersion, let it go. This won't be a big problem once you get more advanced, but for the time being, decide to mine no more than 10-30 cards a day, for example.