Why did some Sufis use rosaries with 33 or 99 beads during dhikr?

In Sufism, the use of a rosary—known as a subḥah or tasbih—serves as a practical counting aid during the practice of dhikr, which is the ritual remembrance of God through the frequent repetition of His names or religious formulas.123

The beads, which typically number 33 or 99, represent the names of God and allow the practitioner to keep track of thousands of repetitions during meditation. By touching the beads one by one, a Sufi can maintain focus on their spiritual practice, whether reciting aloud or silently in the heart. This method has been in use as early as the 8th century to assist mystics in their striving to achieve spiritual perfection and oneness with God. While widely recognized as a sign of piety, the use of these beads has historically faced criticism from some groups, such as the Wahhābīyah, who viewed them as an unnecessary innovation.4231