There's no easy answer because it depends on how often you use it and what type of work you produce (letters or images).
With colour printers you also need to look at the quality of the images.
Take a general laser printer. The business strategy seems to be that there are business and consumer units. A consumer unit might only use a thousand sheets per year so it doesn't have to be very robust. A business unit might demand 20,000 pages per year so would need a different build quality and would cost more.
The manufacturer makes money by selling the toner for the consumer units at a ridiculous price. Typically a basic laser printer is offered at an unbelievable price but the replacement carts can be more expensive that the whole printer.
In that case it makes sense to dump the printer when empty and buy a new one because you then get a printer, a cart and a full 2 month warranty.
my nephew works in a cartridge shop, i need a new printer and hes told me to buy a Canon with my nephew works in a cartridge shop, i need a new printer and hes told me to buy a Canon with indiviual cartridgers, they are cheaper and when one runs out ie yellow you only need to replace that one, i have a laxmark, and they sell their printers cheap but get the money back on the dear cartridges, im still shopping around myself. hope this helps.