I have an in bed RDS tank I bought used. It really makes it nice. I’m a little paranoid and if my gauge drops below 1/2 I get nervous. Below 1/4 and I’m in a panic. So now just as soon as my gauge drops off from full, I know my auxiliary tank is empty and I only have 28 gallons left. I will usually start looking for fuel when I only have 3/4 of my tank left. This will usually keep me above half and out of the panic zone. Depending on where I’m at, that gives me a range of about 350 miles. If I were to run all the way to empty, I could probably go 550 miles or so. For me to run that low it would have to be a life or death situation.