Whats the most reliable method to determine the required battery life for a bike light based on ride time, taking into account variables such as terrain, weather conditions, and individual pace? Should we focus on average ride duration, longest ride of the week, or some other factor entirely? Are there any specific calculations or formulas that can be used to ensure were not caught in the dark with a dead light? How do manufacturers determine the claimed battery life of their products, and can we trust those numbers? Are there any bike light models that stand out for their exceptional battery life, and what features or technologies make them more reliable? Can we rely on rechargeable batteries to hold their charge over time, or is it better to opt for disposable batteries for consistency? Lastly, what role does lumens per watt play in determining battery life, and how can we balance brightness with battery efficiency?