If you work for a printer company, you'll know the score. I believe Lexmark printers are sold at a loss, or at cost (Selling below cost is usually illegal here IIRC) because Lexmark's profit is in cartridges. Their new inkjet cartridges are nearly empty. I knew a girl who was "Tech support" for Lexmark here and her job consisted of taking abuse and telling folks to change their cartridges. The typical phone call was from someone who bought days previously and it stopped printing. If they had bought new cartridges and it still wouldn't print, she put them through to a techie. Inkjet Refillers would put 3 or more times the amount of ink in their cartridges that Lexmark did, for half the price. So of course Lexmark needed tech to defeat that.

Very few folks wear a Lexmark out. They throw it out, and buy a real printer.

I do very little printing so I was advised (I think on this site or it may have been the old Linux Forums) to get a laser printer, because ink thickens and clogs over time, whereas toner powder lasts until it is used.

The only thing I don't like about laser printing is that it comes out as a dark grey rather than black, so it isn't as clear as inkjet printing.

If it's dark grey, your toner is running low, or your refill is low quality. Maybe (perish the thought) buy one original for comparison purposes?

Laser printers should produce completely black output - there is an option on some for "toner saver" or similar that prints with less toner and that may look grey but black text should be black otherwise. With lasers, too, low toner is very very rarely the cause of faded prints - it's usually the drum or transfer roller being faulty that causes that.

That is the original. As to it running low, there's supposed to be a warning light for that and I haven't seen it yet. When I say dark grey, I suppose I mean black but not inkjet black.

It might be worth looking whether there's a "toner saver" setting being used. But, that typed, since toner doesn't go into the paper and toners will vary you might be right and inkjet may make the paper blacker.
As typed above - low toner is very unlikely to cause faded prints. There's a reason why the device will tell you it's out of toner when you can still probably see some toner in there if you look closely and that's so that a guaranteed toner content will be in the developer tank right up until the toner is "empty". What can affect print darkness is the drum (which can be part of the same cartridge as the toner and developer or separate) or the transfer roller or wire which can become slightly detached from its mount causing not enough charge to get on it to correctly pull the toner onto the paper.