Can third party ink be used to refill the ink cartridges?

Why do the ink cartridges run out very quickly?

Replace Ink

Why do the colour ink cartridges run out of ink even though I never or rarely print in colour?

When selecting greyscale printing in the printer driver, does this use only the black ink or all the ink cartridges to produce the greyscale image?

Is there any way to reduce Ink consumption when printing from my computer?

Is there a way to view how much ink is remaining?

Where can I find the ink cartridges for my new Brother machine?