I took my bullseye 1911-A1 down yesterday for a thorough cleaning and lubrication and, by golly, I lost my first gun part. I lost one of the plunger pins for the safety plunger. This is no big deal. It's a cheap and readily available part. But I learned a lesson.
I have done this customarily as part of every complete disassembly and, on reflection, I find no reason to ever remove that assembly again. At least not in a gun that lives either in a gun box, a safe, or my hand all the time, and sees no dirty service.
I think just a shot of gun scrubber followed by a little oil is enough.
The mainspring housing is another matter. I think an occasional cleaning and lubrication is a good idea.
Both of these assemblies are easy to deal with, but do take some time. In the case of the plunger springs, I don't thing disassembly is good for those small parts.