Bismillah
As salam alaikum
I see prayer beads as one of the many bidahs that have risen in the Deen.
I personally stay away from them and even do not condone them. Rasul-ullah used to keep track of his thikr on the fingers of his right hand. I have found that this method is best (of course because it is sunnah). I have heard of brothers that will not do thikr unless they have prayer beads with them. How limiting! Rasul-ullah knew what he was doing with the sunnah of using fingers for thikr. I have no excuse. My counter is always with me. Now we muslims are using electronics to help us keep track of our thikr?!? Beware. Beware. Beware of unnecessary reliance upon dunya. Remember. Thikr is just a finger tip away.
Jazakum Allah Khair
As salam alaikum wa rahmatullahi wa barakatu