^^Why would it make a difference if you leave the line pressurized while not using it? It is pressurized while you are using it.
I realized my post was vague and could be construed as confrontational at best. So I am adding; the reason for the filter is the oil that can come through the extension hoses used to connect to refillable tanks. The filter blocks the oil from getting into the unit. In other words the oil is either present or not, and burning the fuel in the line off has no effect on that aspect.