If you post a photo of your jerry cans (or specify the particular brand) and also a photo of your jeep, I would wager that you will get some specific suggestions for jerry can mounts and storage solutions.
As for whether or not a TJ owner really needs a jerry can, that depends on the situation. This picture was taken in a spot where drivers who ignore warnings to fill up at the last town usually realize that they don't have enough gas to make it to the next one. For those who think there are no such spots in the U.S., please note that there are offroad trails in northwestern Nevada with more than 200 miles between fuel stops.
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