The obvious can pass your mind sometimes
 

My grandfather is always hounding my tail b/c he says "taking the spare and jack out of your car is stupid, you will wish you had it when you blow a tire"

This may be true for trips but not for everyday driving...

Reason: I am on HIS insurance and I pay more to have road side assistance...

If anyone here is scared of taking the spare out, do you have road side? if so, now you should feel comfortable taking that extra 20/25 lbs out of the car.

This should be obvious but some may not even think about it (like my g-pa)

I disagree wholeheartedly. Not to be rude, but I think the fuel you save is insignificant in the grand scheme of things...

*time to wait for wrecker - YOU pay this, late for work, getting somewhere, or whatever, sometimes an hour or more

Other things you don't pay for but we all do...
Gas the wrecker uses to get to you and get you to tire shop or your home
Emissions from wrecker
Traffic backups from onlookers at the wrecker hitching your car up

I'm all about going for it and doing whatever to save, but this idea feels like a loser in the long run. If you're doing it for the environment, it's obviously bad, and if you're doing it for money savings, I can mail you a check for $2.00. That's probably all you'll save over a couple years.

yeah the time you spend waiting is the killer. it can be at little at 10 mins, or up to a few hours, as i once experienced.

to me, it's not worth the time waiting, and i am about as cheap as they come in regards to saving fuel. i always carry an aluminum spare, jack, tire iron, air pump, and a patch kit. it adds extra weight, but 99% of the time i can patch a tyre while it is still on the car, and then keep on going like nothing happened. usually in 10 mins or less.

Yer better off just keeping yer gas tank at 1/3rd to half full... ;)

If you always drive in areas that have cell service with a charged cell phone then sure, but once a tow truck shows up to help you with your flat tire then what do you do? if you had a spare in your truck they would change it for you, now they either tow you back to your house.
I got a flat once while out of state with no spare, it was 10pm on a saturday night, lucky for us the tow truck driver lived only half an hour drive away and took us to his house where he sold us a used tire and wheel, otherwise we would have had the joy of hanging out till the fallowing monday morning for a shop to open up that could sell us a set of new tires, if we had a spare with us we could have fixed it our selves and saved 3 hours, if the tow truck driver wasn't so nice it would have cost us 36 hours.
I also use my jack all the time to look under my car and the cars of other people to see if a wheel bearing is going out, to unstick stuck parking brakes, to fix a tire that had a bulge in it and caused the car to shake violently and to fix the exhaust.

I know my luck... it usually ain't good. But I was able to go several years with no spare/tools and I had no bad tire incident come up either. If you know your track record- how many flats have you suffered?- you can come up with sort of an idea of what the odds are you will be inconvenienced with a flat. For me, when I have really good or new tires on, I simply don't have flats. I just haven't had a problem with getting flats from running over sharp objects. Now, I have had many flats, even blowouts, but that's when I run old, weatherchecked, and/or bald tires. THEN I make sure to have a good spare with tools on board. Changing out those flats has been a very minor inconvenience to me, so it's been well worth it to run those crap tires.

My tires are special order only, so when I'm more than 50mi from home, the temporary spare won't do me a lot of good. I carry a full-sized spare when I carry one at all.

I think you should keep the spare and jack in the car. Better to have it and not need it 99% of the time than to need it once and not have it. If you really need to save on weight you could stop 4 gallons short of filling up. 25 lbs of weight is trivial.

OTOH, I've had only 4 cripling flat tyres in some 600.000 km.
Two of these were caused by vandalism.

Discounting the latter, that's roughly 1 cripling flat every 300.000 km / 200.000 miles ... or 11 years !

I also say I'm in the "It's silly to go without it" side. 25 lbs of weight isn't even noticeable. Unless you're in a fuel competition (or racing) I see no reason to go without a full size spare. I once had a random, unplanned, trip into the great unknown and got a flat tire. Having to take it off, leave your car un-attended in no mans land, and roll it a couple miles (since no cars are around and there is no cell service) to a shop and having them plug it, then having to either pay 20$ for a taxi/hitchhike a ride WHILE carrying a tire OR rolling the tire back (I paid for a taxi) just isn't worth any fuel savings at all. Or monetary savings.

I'll never save that much extra fuel that was used by that ONE flat tire by taking the spare out.

If you want to save weight, just get rid of the asphault in the car. It's only purpose is to make the metal sound thicker while adding a lot of weight to the car. Most cars have this stuff in them, and it's usually in the area of 100~200 lbs you can strip out.