Yes you are right on about vip'ing your self. I remember something about vips being good for a MAX on 1 year and that that was based on 2 fills per week. That boat tanks or rentals should be vip'd every 100 fills expecially if filled by a boat compressor. I dont know if that is a standard,, or if that interpretaion is just making good common sence decisions with in the existing vip process. My class was a PSI class. The instructor also said that we should not revise teh vip date to accompdate an accelerated vip schedule as the date needs to allign with the reining paperwork that goes along with the vip.
mine don't get full vip's more than once a year, but if I suspect there's been any water blown into them, i.e. boat fills, the valve will come off and if there's any rust they have a date with the tumbler, if they look like they did when I vip'd them the valve goes back on, but that's the advantage of being able to vip your own tanks....