Salam If I understand your query correctly, this is the course of action I suggest: do (at least) two khattams before Ramadan. Read every Juzz once (in each khattam) but if you find some that are weaker than others then read those more than once using a divide and conquer approach: say juzz 1 is easy so just read it once. however juzz 2 is kutcha (weak) so read the first qaurter once, twice, or thrice (as many times as you need) and then move on to the next quarter and do the same thing, then read the whole first half. next do the same with third quarter, then move on the the fourth quarter, then read the whole second half. finally you may or may not want to read the whole juzz once before moving on to the next one (depends on how much work it requires).....NOTE: if a juzz is super kutcha (i.e. weak, lots of places where you get stuck or mixed up) then try to read it a few days in a row (4 or 5) in addition to moving on to the next juzz. this is is because the repetition will help. Inshallah you will notice that even a moderate amount of review before ramadan will surely (inshallah) help a great deal with taraweeh during ramadan. or at least this is what i have noticed personally. whereas those ramadans that i entered without having done any intense review before hand i has to spend more time reviewing during ramadan, it was stressfull, and i lacked confidence. also something else to think about when you study something in advance for your exams (moderate amount of studying) it helps it stick better in your mind rather than simply cramping the night before an exam, the same can be said for taraweeh. lastly as an added bonus: during ramadan try to read whatever juzz quran section was covered that night in taraweeh on your own in tahajjud prayer. for example if hafiz A lead the first half of juzz 1 and you lead the second half then after you go home at night either when you get home or before suhoor offer 8 rakaats (or 4) of tahajudd and recite the entire juzz 1, as this will really help you keep everything in your mind and retain it better throughout the year in addition to allowing you to recite hafiz A's section in salah. quran that is recited in salah is superior to quran recited outside salah (in terms of merit/reward) and it also sticks better in your mind, or at least thats what ive been told by several people including my qari saab. this example of "post-exam studying" is effective for long term retention or so ive heard.