Note - we call those cartomizers aka cartos to distinguish them from cartridges aka carts which are what;s used on a separate atomizer.
I use thin clear juices, PG w/ 20% or less VG, avoiding all juices that drop flavoring sediment (clogs cartos, gunks up the coil, shortens life of carto)
I vape 2+ ml per day and I can get 7+ days use out of a Bloog/G6/Volt type carto. I do not use the condom method - I drip jucie in from the top. I make sure the first fill is 18 drops plus however many more it will soak in easily since they are 1 ml cartos. I clean it up and let it settle on different sides for 15-20 minutes after the first fill. After them I keep it damp and avoid singeing it.
When the drag and flavor have degraded too much, I switch to a new one. And so far I have always gotten at least 7 days out of one (and that is 14 days for me because I vape 2 models, each 1/2 the time, maybe the G6-like model a bit more than 1/2 the time, and get 14 days use out of the carto, so I am counting that as 7 days use).