Why do they have 108 beads?
Meanings of 108, according to Shiva Rea, include:
Mathematicians of Vedic culture believed 108 was a number of the wholeness of existence.
The number 108 connects the Sun, Moon, and Earth: the average distance of the Sun and the Moon to Earth is 108 times their respective diameters.
According to yogic tradition, there are 108 pithas (sacred sites) throughout India.
Some say there are 108 Upanishads (collection of philosophical texts written in India between 800 BCE and 500 BCE).
There are 108 marma points (sacred places) of the body.
The 1 additional guru bead represents that you are your own guru (spiritual teacher) and already have all the knowledge you need inside of you. As the guru bead is both the starting and ending point of the Mala, it also signifies the intricate and powerful connection between beginnings and endings.