This is a response to a friend I have on Facebook. I am just going to summarize the statement. He basically said at one point he memorized 600+ Kanji and have forgotten them. There are some key points I would like to address: this guy is bilingual like me except his Japanese is better than mine. I have a deep understanding, but by far he is conversationally fluent except for some instances with economic or medical terminology. A little background on him: his schedule is intense at times with working in the IT field. It is also at graves too. Sometimes he works 12-16 hours.
I think the best thing to do with that schedule is study during the breaks. I use short books like Read Real Japanese during my 15s. We have extended holiday hours so my study time has also kind of short. Since he has a since of fluidity already, I would basically go with half a Kanji lesson to 1 a day. Since 250 Essential Kanji volumes 1-2 are heavy books to lug around, I would probably use something a little more portable, but definitely get the writing time in. You can also use the website www.kanji-a-day.com which has the Kanji broken up into various levels for the JLPT. Probably the perfect books would be Kanji drill series. （漢字ドリル) Since I have other things for the JLPT to study for (i.e. grammar and listening) I use the 1000plus Kanji books 1 and 2.
I know how difficult it is to memorize different Kanji. In fact I try not to. What I do instead is either read them in context, memorize radicals, or try to consistently write out example sentences. I also try to real as much natural Japanese as possible so I do not come off as sounding too text bookish. If any one else has anything they wish to leave a comment providing additional information, please feel free to do so.