For me it would be an expense several years down the road (assuming I don't get myself a Wagoneer by that time and use that for the multi-day long range stuff instead of the Wrangler) although it might be nice to have the extra range if I drive to field camp next summer in New Mexico from North Carolina. I did some bubba math/reasoning-
Its more than half a tank (19 gal stock). I could pick up another jerry can for pretty cheap and have roughly that much gas, but where would I keep it? If I bought mounts it would be within close to that (Morryde side mounts are $150, I don't have a tire carrier to mount on, spare mount for one is $130), plus I need one of those siphons anyway. And those mounts wouldn't lock or anything, so people could jack my cans. Then again, do I have a need for a 50% increase in range, especially on the East coast? If I can get close to 300 out of a tank (say I get 15 mpg, that's 285 mi, 250 with reserves) at that same economy which I'm understating as a buffer, that tank would add 180 miles to my range. So total that's about 450 miles, call it 400 with reserves. The question it comes down to is do I need it. I don't think so. But man that's the deal. We'll see, maybe someone will talk me into or out of it.