There are quite a few variables to selecting a jig head weight. The most important is fall rate. Under most circumstances in the colder water you want a lighter weight to slow the fall of the lure. In warmer waters you want a faster fall rate so go heavier. Sometimes in windy conditions you need a heavier weight to get through the wind and keep a straight line contact with the lure on the bottom. I find for my personal use, I use 1/4 to 3/8 ounce jig heads for most applications. If it’s finesse worm fishing I go with 1/8 ounce. I hope this helps.