Most of Ibadah have set of limits,
5 times/day for Shalat
29/30 days for Fasting
2.5% for zakat.

Except Dzikr....has no limits, as much as one could.... No prerequisites like to perform Wudhu for Shalat, no calculation like in zakat....yet, Dzikr may well be the least activities Muslims do... not sure why, it supposed to be the easiest....

The question I'd like to receive a clarification from those who has ilm is in regard a portion of an ayah being used as a dzikr....Since I've already memorized those ayat I am using them in my dzikr and my friend is not too happy about it.

For example:
"Allāhu 'Aĥadun"
(Qul Huwa Allāhu 'Aĥadun - 112.001)

"'Innahu Kāna Tawwābāan"
(Fasabbiĥ Biĥamdi Rabbika Wa Astaghfirhu 'Innahu Kāna Tawwābāan - 110.003)

"Innahu Kāna Ghafūrāan Raĥīmāan "
(Qul 'Anzalahu Al-Ladhī Ya`lamu As-Sirra Fī As-Samāwāti Wa Al-'Arđi 'Innahu Kāna Ghafūrāan Raĥīmāan - 025.006)

Is this considered a Bid'ah? I hope not since the well known dzikr "SubhanAllah";"Alhamdullillah";"Allahu Akbar" can be also considered as a portion of ayah....