Petrol prices tend to fluctuate throughout the week - they're typically cheapest on Tuesdays and Wednesdays in most Australian cities, with prices rising toward the weekend, so filling up mid-week saves a bit. That said, if we're genuinely headed toward $2/litre, the overall trend matters more than weekly timing, so I'd focus on keeping your tank topped up rather than waiting for a magical bottom that might not come. Apps like FuelCheck let you track local prices in real time, which beats guessing. The excise relief ending does hurt, but driving less or planning routes more efficiently might help cushion the impact more than chasing marginal savings at the pump.