I don't do this on a regular schedule either, I can taste when it isn't giving me a nice clean vape. Again, this depends upon the juice. Some juices will go through a few tanks, others gunk up quicker need it more frequently. I know what they taste like clean and that is the taste I like. I am pretty picky about it too, any hint of a change and I finish the tank and clean it as the next tankful isn't going to get any better and why vape if it doesn't taste right?
Same here. If the color of the juice in the tank changes drastically or it tastes different, I clean it at the end of that tank……if I can. If I'm too busy, I'll half-fill the tank, but I think that's only happened once.
The only downside of using this method that I can find is that I don't know when I'll rebuild the heads……I kind of want to try building a coil around a SS mesh wick……and I've got 4 running vivi novas to do it with……but I've also got a large pile of heads that are still in the packaging. I never expected them to last this long, and it seems weird to tear apart and throw away a coil that's never even been fired. And if I upgrade to a Provari, I'll be able to use all the heads instead of just the 1.8s, so I don't even have the 8 heads I wasn't planning on using available……