BTW I believe
E9 = KR808D-2 (and you can
buy KR808D-2 cartos at AZSmokeFree and those should be the more easily refillable soft-caps - i.e easier to refill the way they were intended to be refilled) and FYI KR808D-2 is not compatible with KR808D-1 (different threads)
Cartos last for about 1 to 15 uses. You run it dry you might get 1. You take care of it, refill while still wet, etc. you might get a bunch of reuses before it dies or tastes bad.
E9 is a rebrander fave for 2-piece and the cartos rebranders sell often have the hard to remove hard caps (or worse glued caps) with the aim of getting users to discard the carto after one use and
buy lots more from the rebrander.