I tend to wait until the light comes on before fueling up again. I've notice it comes on a touch before your #2 line. Maybe a 1/4 of the distance between the #1 and #2 lines, in the direction closer to the #1 line.
folks.. NEVER.. I mean NEVER wait that long to refill it. Do you realize that the electric fuel pump is actually an motor that is submerged in the fuel in the tank.. AND the fuel itself IS the lubrication for this motor. When the fuel drops too low the bearings are not being lubricated by the fuel and can cause premature pump failer. I have seen it many times.. I never let it drop below 1/4
I'm sure Toyota has designed it so that even when the low fuel light comes on there is still gas in the tank. Heck, even if it reaches E, there's still gas, maybe a gallon. On my Acura TL, when I hit E and the Range to Empty is 0, I can still go 25 miles. I've never done it but other people have (as a brave experiment).
Even with that knowledge though, I wouldn't let it run that low. Fill up as soon as you can.
I also fill up again when I get to 1/4 of a tank (or pretty close). I'll never forget with a minivan we had, one day I was driving and heard this DING!...and the "fuel" light came on. I had never heard it before...and didn't even know the van had it! My husband thought I was crazy! I phoned him and told him what had happened.
Hmmm... I would be amazed that letting it get to the fuel light stage could cause such a potentially large problem.
Yes, letting it get all the way to E would not be a good habit, but when the fuel light comes on, I'm never more than a few miles from a gas station and fill up then.
Also, running out of gas, from what I read in the owners manual, is a much bigger deal in newer cars and the RAV than I ever remember it being for older cars. Anyone know how true that really is? Seems like it cause some major issues and things need to be reset or something to get it running again.