I bought a new electric fan for my desktop as a replacement for an older desk fan that stopped working. I suppose I could have had the older one fixed; I suspect that the grease just died on me and that a re-greasing would fix the problem. But I didn't want to do that because I'm quite clumsy when it comes to handling all sorts of mechanical equipment, and I might leave loose screws or damage the unit while doing repairs. (That's the main reason I chose theoretical physics rather than experimental physics--- I'm less likely to cause a mess that way.)
The older fan lasted less than two years. And I wonder why it's so. I remember the old electric fans we had, and I recall that they seemed to last for years. From first grade to at least sixth grade, we kept using the same electric fan and I think that these older electric fans saw use until my high school years. The same thing can't be said for the newer models-- I've never seen the new ones last longer than a year or two. Maybe it's quality control-- I'm not sure though because the problem seems to show up no matter what brand I encounter-- or maybe the grease that's commonly used now is not as good as the older kind.