They are used often enough not to ignore understanding them and learning their meanings. In David's passage you can find 4 phrasal verbs. In Peachey's passage only one (match up ) phrasal verb is used. That is just an example of the possible frequency of their presence in any written text ,could be more or less.You could also write a whole passage without using them. 5000 phrasal verb sounds huge and you could make yourself understood and write comprehensible articles without having to learn all that amount, but if you want to pursue it then step by step and by practicing and reading a lot you might reach your goal. Good luck:)

Five thousand?? ':) I think you should just learn to identify and take note of phrasal verbs when you encounter them (as you would do with slang and idioms). We are continually creating phrasal verbs, plus the same phrasal verb may have different meanings, so I'd suggest trying to understand how they work in concept instead of matching up definitions. As to advanced communication... well, phrasal verbs sit comfortably in common or informal speech. It's very rare that an academic or formal writer would rely heavily on phrasal verbs. The good news is that there's always a formal equivalent to a phrasal verb. :)

All the time!

I guess so, check out the wiki page on phrasal verbs: http://en.wikipedia.org/wiki/Phrasal_verb all of those phrases seemed very commonplace to me. There were several instances where the article makes points about word order, i.e.noun before adverb, sometimes these seem overworked. Make sure that anything you're working hard to memorize holds up in conversation and print materials. Keep in mind that most native english speakers, myself included, don't know when they're using phrasal verbs! This brings up the interesting point that phrasal verbs in their idiomatic usages probably contribute to many mistakes made by english speakers when trying to learn another language. Think of common mistakes that english speakers make when learning your native language where the words they're using just don't make sense together. You'll probably find that if you translate them word for word back to english they might make perfect sense to english speakers and also appear on a list of phrasal verbs! If you have a good library of wierd phrases used by english speakers in your native language you might have a ready made list of phrasal verbs and indiomatic phrases just waiting to be translated verbatim into useful english! Let me know if this turns out to be helpful to you.