Hello fellow vapers, I hope all you moms out there had a great Mothers Day!! Im curious, is there a normal refillable time on cartos or do they all differ? I bought a standard 510 low res carto last Thursday and have refilled/topped it off maybe 6 times and I am not getting near the vapor production/flavor that I was getting the first few times that I filled it. Is this normal? Do cartos not last very long? Thanks for reading.