I am too busy and Hebrew is too difficult to maintain after college.
Hebrew is a difficult language to keep up. I am not speaking from a great deal of experience being only out of college a few months, but the following are ideas that I have heard from others or am intending to follow myself:
i. Most importantly be convinced it is important. Perhaps this post is in the wrong place as we haven't dealt with all the objections yet, but unless you are convinced that it is worth keeping up with Hebrew you never will.
ii. Practically, I think 'little and often' is the key. I have worked out that I have about 15 minutes a day to keep up my Hebrew, so I try and read as much as I can in that length of time. But however much time you have, it seems better to do it every day than just reading big chunks once a week say. I also try and read aloud which helps with my concentration.
iii.One of the books that I have been most excited to buy this year is the Reader's Hebrew Bible. This contains the text of the BHS but footnotes every word that occurs less than 100 times in the Hebrew Bible. This has two advantages. Firstly, it means that you can read the Hebrew text without constantly looking up a lexicon. The editors label the footnotes as 'glosses' – which they are. And they emphasise that they should not be used instead of lexica for detailed exegetical work. Secondly, when you come across a word that does not have a footnote, it means that you should know it. This forces you to pause and try and remember the word rather than simply looking it up. Words that appear more than 100 times are listed in an appendix and as there are only about 500 (?) of them, this is a manageable amount of vocab to maintain.