I’m planning on buying a laser printer but concerned about the life cycle of toner in the machine

Will it start to clump in the printer after 6 months?

Very unlikely unless you're keeping the toner in an especially warm and humid location.

I purchased a Samsung Laser MFD (CLX-6260FW) over two years ago, and I've had no issues with it. It came with a set of "starter" toner cartridges:

• Black - 1503 impressions / 2000 page capacity
• CMY - 645 impressions / 1500 page capacity

About 1.5 years after receiving it, the cartridges each showed as "0% remaining" and required "immediate user intervention" so I purchased more to be prepared (6k Black, 3.5k CMY), but a further ~7 months later, the original cartridges are still going strong. Others have suggested that toner can still be good after ten or more years.

Toner cartridges can benefit from a gentle shake (side-to-side), which helps to redistribute the contents, but this tends to be required when they start to get low and show print issues... rather than due to toner clumping up. Be wary of vigorous shaking, as any toner leaks / spills will be a significant issue (for both cleaning and respiration).

I flat out refused to buy a printer for a long time, but it's become more necessary for me in recent years. I decided against any inkjet technology (including HP PageWide / fixed head printers, which can be presented similarly to a consumer) for a number of reasons... critically:

• Idle Inkjet printers get "gunked" up very quickly - if you're not printing regularly, then the head quickly becomes caked in dried ink, which requires careful and expensive cleaning (ink is expensive) - potentially requiring hand cleaning or even a replacement head (or whole printer)
• Running costs: replacement ink is incredibly expensive, and DIY refills are becoming harder and harder due to DRM - Printer Ink is one of the most expensive liquids in the modern world - See "Ink Cartridges are A Scam".
• I've long maintained that "printing is the weak link in computing" - Inkjet printers have a habit of jamming, chewing on paper, wearing out... mechanically they are far from a sound idea

With the price and size of laser printers now, I'd recommend that nobody purchases an Inkjet ever again (budget permitting of course, they are still a bit more expensive in the short term).

While laser printers are quantitatively worse for high-quality photo printing, I'd suggest that unless high-quality photo printing is a very important and regular use-case for you, laser will be just fine. For occasional high-quality photo printing, use an online service.

To expand on the running costs of an Inkjet printer briefly, consider some random HP cartridges.

While the upfront cost is much higher, the running cost is significantly lower (probably better than ~50%).

HP Inkjet Black Ink Cartridge

• HP "No. 45", claims a coverage of ~930 pages, for £44.95
  • 4.8p / page
• HP "No. 300XL", claims a coverage of ~600 pages, for £36.73
  • 6.1p / page

An approximate ~5.5p / page of black and white only printing... completely ignoring the use for alignment, head cleaning, wastage due to being dried out, wastage due to re-prints, wastage due to DRM, etc...

High capacity inkjet cartridges (e.g: HP 973X) can work out dramatically cheaper than this on a strict per-page calculation, though their high-capacity nature will incur a far higher cost due to wastage for infrequent printing.

HP Laser Black Toner Cartridge

• HP 1500, claims a coverage of ~5,000 pages, for £100.50
  • 2.1p / page
• HP 642A, claims a coverage of ~7,500 pages, for £206.23
  • 2.7p / page
• HP 645A, claims a coverage of ~13,000 pages, for £320.95
  • 2.5p / page

An approximate ~2.4p / page of black and white only printing.

Not to get dragged into a laser vs inkjet debate (laser is far superior.), I will simply add my experiences using lasers.

Do not be worried about the toner going bad. I have never had it happen, nor heard of it going bad.

I have a Brother H-2140 sitting next to me now, it was manufactured in January 2008. It gets little use. The toner in it now is over 2 years old (and that is only the second cartridge in its entire life). So using (very) old toner is not an issue.

There are a host of HP laser printers at work, all with mixed amounts of use, some with OEM toner others with cheap ebay toner. Some machines sit unplugged for long periods of time until needed, no issues with toner in any of them.

Under no circumstance would I consider buying an ink jet, especially for infrequent use. An inkjet will either use up all the ink sitting idle, or if you unplug the printer will ruin it. The ink really can dry up and clog the print head, (have had it happen).