It is the sunnah of the beloved prophet SAW to set a time of the day and night to read the Qur-aan and to do the zikrullah.
It is reported under the authority of Ibn Majah that once the beloved prophet SAW came later than usual to visit the tribe Thaqeef. They asked him the reason for his lateness. He replied: ‘’I had some quantity of Qur-aan left to be completed, so I disliked to come out without completing it.’’(Ibn Majah)
A Hizb is mainly a set quantity of Qur-aan to be read daily. One may set the daily Qur-aan reading quantity or hizb according to one`s time availability. But if possible, recommended to read one parah daily. This is the hizb that the beloved prophet SAW set firstly to Abdullah Bin `Amr r.a. (Muslim Shareef). That is to complete the Qur-aan in one month. This is where the terminology of Parah have been introduced.
But if you are unable to do a hizb of one parah daily, then do half para or quarter para or whatever number of pages you can during your free time. Better set something little but you would do easily daily.
In a sahih hadith of Ibn Majah, the beloved prophet SAW advised us: ‘’Set your habits of good actions as per your capacity. Because the best action is the one done continuously, even if it is a little.’’(Ibn Majah)
سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ اكْلَفُوا مِنْ الْعَمَلِ مَا تُطِيقُونَ فَإِنَّ خَيْرَ الْعَمَلِ أَدْوَمُهُ وَإِنْ قَلَّ سنن ابن ماجة
So set the number of pages of Qur-aan you will read today. And set the time that daily you would read them. Also set the place also. A good time to read the Qur-aan freely is at Fajr time.
Besides Qur-aan reading, set a number of Zikrullah daily. Because Allah Ta`ala ordered us to do lots of Zikr, especially before Sun rise and sunset. So after Fajr salaah and after Assr salaah try to read these zikrullah:
100 times Astaghfirullah
100 times Douroud Shareef
100 times Soubhanallahi walhamdulillahi wa laailaaha illallah wallahou Akbar
You may read the kalimah Tayyibah 100 times and also Allahoumma inni as-aloukal jannata wa arouzoubika minannaar.
With these set of hizb, you would be progressing spiritually. A hizb is important for spiritual progress. That is why the beloved prophet SAW advised us to replace or to complete our hizb when missed at its set time.
It is reported on the authority of Abu Dawood that the beloved prophet SAW said that whoever slept at the time of his hizb(tahajjud time), so if he complete the hizb between ishraaq and Zohr, it will be written as if he read it during the night’’
Also reported in Muslim Shareef that when the beloved prophet Swalallahou `Alaihi Wasallam finished his Fajr salaah, he used to stay in his musallah sitting until the sun has risen up brightly.’’(Muslim)
عَنْ جَابِرِ بْنِ سَمُرَةَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ إِذَا صَلَّى الْفَجْرَ جَلَسَ فِي مُصَلَّاهُ حَتَّى تَطْلُعَ الشَّمْسُ حَسَنًا مسلم
And finally set at least 2 rakaats of tahajud as a minimum salaah for the night. Because it is said in a hadith that the one who did not read 10 ayats in tahajjud salaah during a night, then he would be between the ghafils(distracted). So each night, before you sleep or after your Esha Farz and sunnah, read 2 nafils with niyah of tahajjud with at least 10 ayahs(the last two surahs of the Qur-aan have 11 ayahs).
In brief, ask Allah Ta`ala help during this Mubarak time of Ramadhaan to set up a minimum hizb for life. Then inform us for an inventory time to time.
And know if you happen to miss your hizb during sickness or travelling, the sawaab will still be continuously be written in your books as it is reported in different ahadiths.