In my opinion, a man knows 300-500 characters can understand almost all Chinese posts. 5000 is too more for common people.
Leaning Chinese is very difficult at beginning, but easy at last.
Leaning English is very easy at beginning, but diffcult as last for you must learn more and more words. Chinese characters don't go up for 3500 years, this is why common Chinese can understand those articles written in 3000 years ago without translation.