According to the ES 350 Owner's Manual (see page 354 in the 2022 pdf version) for the ES 350 2WD model when the low fuel level warning light illuminates:

 

I wouldn't do it unless emergency.

 

I can confirm this. I hand calculate every fill up.

I routinely have 3ish gallons in reserve once the light goes on.

 

You wait for the light before every fill up?

 

I fill mine up when it is at half mark every single time.
I did this to all my cars and no fuel pump/injector issues..
There were very few times that I saw the fuel light.

 

Yes... every time.

I drive 120 miles per day. If I filled up every time I hit the 1/2 tank mark I would be living at the gas station.

 

I would be concerned about overheating the fuel pump often - that's all but I understand your dilemma. Prius might be a good solution

 

It is OK to use all the gas until you see the reserve light. Driving the car with very little fuel in the tank will ruin your tank fuel pump which is not too expensive. But running on empty will ruin both pumps including the high pressure pump, and the direct injectors. That is a real PITA.

 

I fill 'er up whenever the gauge is at 1/4 remaining or so. During the 3 minutes this takes, I often think of my Tesla-owning friends who spend 3 hours to fill their cars up with electricity.

 

That's correct if you are using public chargers.
At home, you just plug it in at night and forget about it till the morning.
But you are right.. Still doesn't change the fact that it takes hours to charge.
Let's say you have some emergency and you need to go NOW.
Because you have been driving your electric car all day, you have almost 20kms left...
With the gas car, you have 3 minutes and can get 430miles range.
With the EV, in 3 minutes, you may have added an extra mile range.