Every day you must read some of the Qur'an. In fact do not consider a day complete unless you have spent some time with the Qur'an. It is better to read regularly, even if it be only a small portion, than to read long parts, but only occasionally.

Allah likes things which are done regularly, even if little, said the Prophet, blessings and peace be on him (Bukhari, Muslim). He also warned especially that you must attend to the Qur'an regularly, otherwise you may easily lose your gains. The parable of the companion of the Qur'an is like a tethered camel; a man holds on to it so long as he attends to it, and it escapes if he lets it loose (Bukhari, Muslim).