For the Penny Pinchers...
Take this into account, if premium is $0.25 above the standard 87 octane gas (overestimate):
-- Your maximum fillup is around 10 - 11.5 gallons depending on which sr powered car you drive...
-- Your maximum difference if fillup price from 87 to 93/4 would be $2.88 more
-- If you filled up once per week every single week of the year, you would only be paying $150 more per year.
It's not that much more really... so I use premium in all my cars, and I always have. But it doesn't really hurt to use regular.
Don't eat out for a week and you can afford premium!