I've seen read a lot of books where they use different sign conventions for the metric and the covariant derivative. I'd like to ask the physics community the following questions: I've seen both, the (+, -, -, -) and (-, +, +, +), conventions used for the metric, and I've also seen both, [itex]D_\mu = \partial_\mu + i g T^a A_\mu^a[/itex] and [itex]D_\mu = \partial_\mu - i g T^a A_\mu^a[/itex], in the literature. 1. Which convention, for the metric and the covariant, do you use? and, 2. Why? Do you find one more convenient over the other? or were you brought up to believe in one convention, and has it stuck with you ever since?