If you are going to leave the pressure on for several days at serving temperature, you should set the pressure to the desired serving pressure. At 30 psi and chilled, one day should be enough.
Just purge the keg a few more times.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
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