The problem I have with the Safari is that I don't write much and they dry out before I use them much. My Kaweco Sport lasts for ages, and I think it's to do with the fit of the screw top compared to the relatively loose clicking mechanism of the Safari cap.
I use a refillable cartridge on my pens and have dialed in about how much ink I should load at any given point in time based on my writing habits. It might help to play around with that.
