Right. One of my points was that things you do once a year are difficult to make a habit. For a long time now synthetic oils have been good for 10 or 15k miles but people still had 3k or 5k intervals drilled into them so maybe once every few months was on their internal clock but once they actually took the time it ended up being twice or even once a year and that was actually fine.. But let's say the interval is now a year and you do it every 18 months? Is that fine? I don't know..