Digital BW, The Print

I just bought an Epson R2400 printer and am getting to the end of the
initial cartridges in verying degrees. Not all of them are running out
equally as would be expected. I have a complete set of MIS K4
refillable carts to replace them with. My question is should I remove
all of the initial Epson carts and replace them with the MIS carts or
replace them separately as they need replacing? I realize I'll need to
create a new printer profile for the MIS K4 inks for the papers I use.
All feedback will be appreciated.

Your friend in Photography,

Johnny