I have no clue what ya'll are doing to your cartos, but I'm still running off of the same 2 I got from a starter set for just over a month now. They have never been cleaned nor have they reduced in draw. I vape only Johnson's Creek in them too.
Here's the thing- you'll never know the draw has been reduced until you load up a brand new one. The change in draw is so gradual that you just can't perceive it- it's not like you load it up one day and notice a significant difference. But when you load up a brand new carto and take that first drag, that is when you realize the old one did actually change.
Yeah, I could run a carto for a month+, but I truly prefer the looser draw that a brand new carto gives.