Invisible Choices, Made by Default

Anki might not be suitable for anything other than vocabulary extension (and medical school). I'm not really sure. I've only ever successfully used it for vocabulary extension.

I may be biased because I use Anki to study Chinese, an unusually difficult language. The relative merits of Duolingo vs. Anki may be less clear-cut for easier languages like Romance languages where it's not necessary to learn the language so systematically. In the case of Chinese, grammar is so simple and vocabulary is so hard that vocabulary extension is pretty much the entire game, so optimizing for anything other than vocabulary acquisition can cause you to fail in the long intermediate slog.

What language(s) are you studying?

I find Duolingo way better for getting a feel for grammar.

This makes sense. I prioritize vocabulary over grammer for a couple reasons. [1] You can communicate effectively with vocabulary and without grammar (but not vice-versa) and [2] the difficulty of learning a language's grammar is far outweighed, in the long run, by the difficulty of learning vocabulary.

It may make sense for someone to start learning with Duolingo and then transfer to Anki (for hard languages) or just reading material in the language (for easy languages). I'm happy to hear that Duolingo works for you.

Starting with Duolingo might be OK, but it’s very bare-bones and unlike the real deal of having thoughts in a language and then expressing yourself. In fact, I recommend not using it after you have a rudimentary grasp of the language.

Try entering full sentence-to-sentence cards in Anki. At first, you won’t be able to write good sentences on your own, so use a sentence-search service for that (I don’t remember what they’re called, but at the least you can use the example wordreference sentences). Over the course of a year, I input all the thoughts I’d had that day which I couldn’t translate. By learning to produce words in-context instead of memorizing the multilingual dictionary, I began to run out of additions to the Anki deck. That exercise gave me near-fluency, which has persisted to this day.

So, I think Anki is suited for nearly everything except oral skills. Plus, spaced repetition saves time.

Also, you might try an app like Tandem. If you’re single, try learning to be interesting in the foreign language - it’s naturally motivating, and both of you can chalk up any awkwardness to mistranslation. :)

I've found Anki really terrible for learning, even for simple things like vocabulary; what it does is help me remember things I've already at least half-learned.

Spaced repetition is almost designed to be difficult. The method works best when you are presented with questions that are at the limit of of your abilities. If you see a lot of cards that are easy to answer you are probably wasting a lot of time. Therefore, when it works well you are seeing a lot of cards that are hard for you to answer. I think that feels bad for a lot of people because only being presented with the hard cards makes it seem like they aren't good or improving at the thing.

Actually making the cards is what stops me.

Spaced repetition is inherently difficult because it requires a period of intense focus. It you're doing it efficiently it's hard on a minute-to-minute level. In my personal experience, it's the most intense form of study I can scale up. When I'm using Anki, it's the hardest 10-15 minutes of my day.