Flashcards are worth it

Benefits of spaced repetition systems (Anki) go beyond saving time looking up facts.

Displaying competence: They enable you to present as highly competent in conversations where you have a copious number of precise, relevant facts off the top of your head. This can increase the opportunities available to you at work, and make you a more stimulating and credible conversation partner in social settings.
Context and connections: It gives you hooks to recognize the relevance of new information to previously memorized facts, so your memorized background knowledge fills in when presented context is inadequate or misleading.
Avoiding reasoning errors: By enabling you to remember precise definitions, memorization enables you to avoid costly reasoning errors that can be caused by conflating definitions.
Engaged reading: You’re always asking “is this fact worth flashcarding?” “How many cards should I limit myself to making today?” “What’s the best way to turn this into a flashcard?” This gives you something very productive to do with any arbitrary text you read.
Long-term efficiency gains: You’ll always be under short-term pressure to produce. Flashcards enable you to build the foundational knowledge to yield long-term improvements in your information gathering and decision making (declarative knowledge about diet, exercise, and cognitive science, employment opportunities, the literature in your field, new work tools).
Procedural practice: Some of my flashcards are just hyperlinks to Wolfram Mathworld computer generated and graded mathematical practice problems. I bury these until I have pen and paper available. There are lots of such computer generated problems out there, many of which are either presented as problems to do once and never again, as expensive but limited subscription services where the SRS aspect is a major selling point, or that have endless problems but don’t include any SRS aspect. Anki turns any of these into a centralized SRS system along with all your other flashcards, simplifying the process of engaging with these resources.

Each card will take time to practice. Thinking about all that accumulated time discouraged me, at first. The costs are lower than they appear at first.

Exaggerated practice times: Anki counts any time you have a card open in the app as practice time, even if you’re not actually looking at your phone. It will systematically overcount the amount of study time, leading to misleadingly high estimates of the time it takes to practice.
Learning curve: Making and reviewing cards are interlinked skills. Early in your Anki experience, the time cost/learning benefit ratio will be substantially worse than after you’ve gained more experience. With experience, you’ll get faster at making better cards that give you more value while taking less time to answer.
Time niches: Anki practice can occur in sporatic bursts at convenient times that aren’t a good fit for your main work: on the toilet, on the bus, on a coffee break when you don’t feel like talking, as an alternative to scrolling the internet or before-bed reading, as a way to relax when you’re overstimulated at a party and go into another room for some quiet time. It does not have to compete with your most meaningful activities. Instead, let it replace your least meaningful activities.

I’m curious whether it’s possible to turn a resource, like a math textbook, into flashcards in such a way that you memorize the flashcards themselves, enabling a purely mental flashcard review. Notably, I find that as a card matures, I become so confident that I got the answer correct that I no longer need to check. This supports my belief that purely mental flashcard review is possible.