Personally, my limit is 0.09 for single cell mechs with a samsung 25r. I'm now running 0.12, but I just mean that I theoretically would not go under 0.09, and have only run a 0.09 shortly one time, but rebuilt because of not completely happy with it(first time making dual parallel 22g macros KA1)
I don't recommend this to other mech users, and the recommendation to go by CDR is good in general for people, but my personal stance is that
vaping is pulsing, but however, we cannot just go by pulse-ratings in general as there's no standard for how long pulses are tested at, but we can however, for each cell, check the battery specs, to see what the pulse-ratings corresponds to, e.g. the samsung 25r is 5sec pulses of 45a and 100a for 0.5sec etc. Those values are the ones I personally use as max values, but again, not recommending out to people! When I say max values, then I mean also max values with also time to quickly dump the cells out if stuck fire-button!
This obviously applies, that I a) don't ever leave a "loaded" mech/atty unattended and so take the cells out if going out and b) I make sure to be on the lookout for that if any stuck firebutton, then I quickly needs to take the cells out.
That's just me though
And for the third time, the above is my own usage and not my recomendation!
Btw, I always say to myself, I never want/need to go lower than this, but then after trying a quick time a little lower build, then it's hard to go back to the older builds, since the warmth and thick dense vapor is just so fulfilling, so my limits has gradually dropped lower and lower down I must admit, and i'm no cloud-chaser at all, but just love to inhale/exhale nice thick dense vapor very much