There are several advantages to keeping your tank above half full:
1: Filling the tank doesn't cost as much per fill up.
2: It will help prevent partial tank fill ups here on Fuelly.
3: You will have plenty when/if an emergency occurs, such as getting stuck on the side of the road in winter, or having to take a trip to the hospital, etc.
Also be sure to always fill your tank the same way every time you fill up. This helps give you accurate mileage results.
by DTMAce on February 21 2012
this tip works for 29% of voting Fuelly members.