It looks like my Topeak Road Morph died sometime over the winter. I had a flat a few days ago and it wouldn't pump up when I needed it. I made an effort to keep the plunger lubricated over the winter, but a lot of road grit still got into it. Part of this may be that I don't have full fenders on my road bike, just a set of minimal clip-ons. The seat tube, where the pump is mounted, isn't protected and gets quite a bit of grit sprayed onto it. The failure wasn't something I'd chalk up to a manufacturing defect or design flaw, it was definitely due to blatant abuse.
The Road Morph has been replaced with a Lezyne Road Drive. The Lezyne looks like it is sealed much better; between the rubber caps and the internally-stored hose it should be less susceptible to getting road grit inside. I'll miss the inline pressure gauge, but that's an acceptable loss.
Now, you may be asking yourself how I got home if my pump didn't work? Simple answer is that I'm extremely paranoid and so I also carry a CO2 inflator in my saddle bag. Actually, I'm not that paranoid; I just have the CO2 there in case I get a flat on the way to work or in really bad weather that I want to get out of.