One of the basic essentials in pool and billiard play is pool cue chalk. Without a well-chalked cue stick, it's almost impossible to get the kind of cue ball control and finesse you need to play a quality game of pool. Skilled pool players chalk their stick before nearly every shot to insure good cue contact and prevent miscues. Chalk is cheap, and it’s also cheap insurance against a bad hit on a crucial shot.
If you own your own pool cue stick, do not use chalk from a bar or pool establishment. Most pool halls purchase the cheap chalk and most people are not sanitary with the chalk. Already in the chalk hole there could be dirt or grease, or who knows what.