a lot of people are often held back in their memorisation because they feel what they have already memorised is weak. They then put their hifdh on hold in order to go back and perfect these surahs with the hope that once they have strengthened the “older” surahs they will move on and memorise “new” ones. As much as it may seem sensible this is not a good idea at all and Allaah knows best!
Memorisation of Qur’aan is a 2 part program, the 1st being hifdh and the 2nd revision. We should always be doing both at all times i.e everyday. If we find we’re forgetting things from a surah we already learned, then instead of stopping hifdh we need to improve our revision timetable and maybe technique so that we can improve and strengthen our memorisation. If you feel uncomfortable doing this then you can reduce the amount you are memorising per day to make things easier.
A teacher once advised that we should “never let a day pass by without memorising” and this is very true. Always make lots of dua for ease .
May Allaah make it easy for us to preserve His speech and may He make us sincere in our quest to do this and may He accept our efforts from us.