I plan to go that route eventually, but not until some of the original toners start registering "empty".
Depending on the design of the printer, that might not be a good idea.
HP laser printers (and for all I know, many others) provide more than toner in their toner cartridges. You get a new drum, new seals, new doctor blade, new developer, and new high-quality toner.
OEM toner cartridges have a designed service life equal to a little bit more than the quantity of toner inside. You can refill them, but you are using a worn-out drum, risking damage (sometimes irreparable) to the printer itself if a seal fails and dumps all the toner into the guts of the printer.