lasers use toner and fuse it to the paper, it won't run or fade if it gets old or wet. Inkjets use liquid ink that dries on the paper, most of it is water soluable and it fades somewhat over time.
Some lasers use a toner cartridge with a built in imaging drum (more expensive cartridge), some keep the drum separate(less expensive cartridge). The drum has to be replaced every so often so it can be an additional maintenance expense.
Cheaper (in price) lasers generally have the built in drum type of cartridge.
Most inkjets are designed as disposable technology. Stuff goes wrong with the heads or the waste ink reservoir gets full and you toss it for a new one. They work well as long as you use them regularly. Not necessarily a lot, just enough to keep the heads from drying out and clogging.