This system takes into consideration only the last 30 days, so you'd have to report at least one price per day to maintain the top spot. Once you miss a day, it takes 30 consecutive days of price reporting to make up for that missed day. If, meanwhile, another member reports steadily, not missing a day in 30 days, they will pass you in the list.
In order for prices to be displayed and for top spotter, champ, awards, challenges and leaderboards to calculate properly, GPS is required and price reports must be made while physically at the station. This is done to reduce recent abuse (people making up prices for stations in areas other than where they are currently located, etc.).
Never use GasBuddy while driving. Please only use GasBuddy when safe and legal to do so.