If we only burned fuel for necessary things..ie going to work, the hospital, school etc how much could we save

you would save plenty on gas, only to have to spend it some where else.

Interesting question. What % of our fuel was for work, and how much for other?
Let’s see: I work from home; my husband works 10 miles away, =100mi/wk. His flight to Russia was for work.

Other? Let’s see, I flew to Texas to see my ailing father.
2 trips to train station/wk for daughter=40 /wk;Philly 1/mo other daughter =15 mi/wk. Son comes here=0 for us parents. Family visits, say 40mi/mo…..of course, the wedding in NH skewed things. But this doesn’t count shopping trips, errands,visiting friends…..however, my husband has this Real Thing about “Combining Trips” so as not to be wasteful of car use, so I think we probably do better than the Average American in these areas.

But I didn’t really totally answer your question, Bearcat, because you were also talking about super-luxury items like jet skis and speed boats which most of us don’t own.

Still, I’m sure Americans in general could cut fuel use by more than half if they did away with luxury fuel-consuming items and unnecessary travel –but the easiest way to go is by:
1. Cutting commuter fuel use by living close to work, car pooling, or using public transportation, 2. sticking with fuel efficient vehicles, and, 3. Dumping the people you love, like your adult kids.

Let me comment that all 3 of my adult children live in cities–Philly, Brooklyn and Manhattan– and not one of them owns a car now. They all get around by public transportation, (‘cept when Mom and Dad pick up my youngest at the train station). Public transportation DOES WORK when the public is willing to use it.