Do you define your target vocabulary?

[Cavesa]

For people who are interested in learning lots of languages though, I could see being more picky about what words one learns as beneficial.

I don't think that is being discussed here. Learning several languages doesn't mean being picky as if we had only a limited amount of word slots in the brain and had to divide them among the languages. There are exceptional people, like the guy who learnt a French dictionary to win a scrabble tournament, who show us we are far from reaching our total capacity. Sure, it doesn't mean that every human being can do that, just like not everyone can run like Usain Bolt. But it is safe to believe we can learn much more than we think.

It is rather the opposite, we are improving the vocabulary, even when learning several languages, and the question is how many words are enough for each learner.

I find it interesting that some numbers get repeated on the vocabulary books' covers, titles of memrise decks, and so on. The numbers I can remember seeing are :
1000 (ok, we'll probably agree this is not a serious "final" goal, it is just an easy set of data app creators can give a new cover to enjoy the profit),
2000 or 3000 (serious traditional courses),
4000 (various vocabulary books, supposedly the vocab for GoetheB1),
5000 (a nice number perhaps, various memrise courses are a good example),
10000, 13000, 15000, and 20000 are still in my library as vocab books "to be learnt".

Jumping a bit higher, 35000 is already a middle sized monolingual dictionary, therefore originally not meant to be memorized. But the awesome +French courses on memrise by Eunoia make up to approximately 35000 words too.

Looking at some random rarer words on the +French lists (based on the Lexique database), I think 35000 is not an unreasonable passive goal for anyone regularily reading in the language. Especially considering the overlap between various european languages. The deeper in the frequency you get, the further you get towards interesting not everyday stuff, the more overlap you find. Even in not obviously close languages like Czech and French, and of course not all these words are totally original, a noun and the verb from the same root are counted separately, and so on. As active vocabulary, 35000 is quite a challenge, but potentially very rewarding as that might be quite close to usual natives. The authors of resources my little number list comes from seem to suggest that something like 15000 is already absolutely awesome for a learner, and something like 4000 is B1, therefore covering most everyday situations and conversation topics.

[trui]

I don't think that is being discussed here. Learning several languages doesn't mean being picky as if we had only a limited amount of word slots in the brain and had to divide them among the languages. There are exceptional people, like the guy who learnt a French dictionary to win a scrabble tournament, who show us we are far from reaching our total capacity. Sure, it doesn't mean that every human being can do that, just like not everyone can run like Usain Bolt. But it is safe to believe we can learn much more than we think.

No, there's no real brain capacity limit but there is a time limit. One can only learn a certain amount of words a day and thus learn only a certain amount of words in one's lifetime.

However, I agree that learning related languages helps one to fit more languages into one's lifetime and I agree that we can often learn much more than we think though I do think that it's a good idea to try not to bite off more than one can chew. But it's better to bite off more than one can chew than to not take a bite at all.

[zenmonkey]

As active vocabulary, 35000 is quite a challenge, but potentially very rewarding as that might be quite close to usual natives.

I'm not sure what you are defining as active vocabulary there but the average native speaker of a language tends to actively use quite less than 35K words. They may know and recognise that amount but that is the passive vocabulary.

A native actively using 35000 different words (lemmas) in a year is a rather unusual native.
I'm not even sure how they test active vocabulary.

[coldrainwater]

tldr; my goal is to create and maintain a list of roughly 10k interesting and unknown words in my TL.

If I were pressed (in ink), I'd say reading was and still is my primary goal with respect to learning my TL. Lifelong reading in my L2 is my plan to keep from losing my skillset over time. Love of words may be a thing of nature, nurture or both for me, but it is there to stay. Before I knew anything about learning a foreign language, I had one piece of data that meant something to me. It is a small notebook that contains, by my rough calculation, eight thousand low frequency/advanced English vocabulary words that I wrote down as a teenager and wanted to learn in the English language. Looking back on the list, I am very glad to know the bulk of them today. Some are unfamiliar but most are at least at a passive level even some 20 years later. A few I laugh at and wonder what on earth I was thinking of when writing them down.

I restarted learning my L2 one year ago after a typical US false beginner Spanish path. I remember I wanted to make a list of 10k personally interesting and unknown vocabulary words and then learn them to a point of at least passive recall (good enough for government work). What I didn't count on is that making the list might take me a very long time since I am intentionally staying far away from vocabulary acquisition (all my other areas are far weaker even with zero current vocab study). Over time, I will need to look over the list and remove words that I feel I know too well. If my judgment lacks, then they may show up again. My weaknesses in the other language areas will last a long time, but not forever. When that time is up, I'll most definitely engage with vocabulary and enjoy the heck out of the experience. Getting to that list of 10k interesting and unknown words is definitely very motivating for me. I could 'cheat' and get the list faster, but I want my natural language exploration, which is likely to be heavily word-oriented, to lead the way.

[Voytek]

How many new words daily you try to remember guys?

For me it's about 10 English ones and 30 for both Spanish and Swedish.

[aokoye]

How many new words daily you try to remember guys?

From a little less than a year ago - How Much Vocabulary Every Day

[Tillumadoguenirurm]

I try to only write down the most important or the most common words, mostly picked from course/textbooks or newspaper articles, but sometimes I treat myself with a list of really neat or strange ones.

And writing down is your only method of remembering words?

Some of the words I make a private memrise course for and others I just memorise from my notebook. Learning words without context usually isn't a problem for me, I recognise them when I see them in a text anyway, though if I'm in doubt about a meaning I double check before "memorising" the word. A few other words I just remember after seeing them or writing them down.

[Cavesa]

As active vocabulary, 35000 is quite a challenge, but potentially very rewarding as that might be quite close to usual natives.

I'm not sure what you are defining as active vocabulary there but the average native speaker of a language tends to actively use quite less than 35K words. They may know and recognise that amount but that is the passive vocabulary.

A native actively using 35000 different words (lemmas) in a year is a rather unusual native.
I'm not even sure how they test active vocabulary.

I don't think the 35000 list or dictionary consists of 35000 lemmas, there will be fewer of those, and a lot of the worlds will be sharing stems, so the amount of stuff to learn is not as high as if it were 35000 completely unrelated words.

I don't think it is important how many words does the native actually say during one year. One year is not that much. I find just as important all those words you don't need to say but could, if the need arrived. There are people who will not use the word hammer even once during the whole year 2017. Nonetheless, they know it just fine.

And truth be told, my crazy and impossible dream is not to speak like an average native, but more like a well educated (therefore not that usual) one.

[Voytek]

I forgot to mention that I also add words and useful phrases from mini-dictionaries for tourists.