This is just an observation, I'm not picking on anybody, but the machines that are lubed according to factory instructions are more likely to wear out than the machines that are over oiled.
Domestic sewing machines do not have oil reservoirs, they depend on the oil film between the shafts and the bores they ride in.
One drop every 6 months or so is no were near enough with a machine that is used a lot.
The machines I've acquired that are awash with oil and it's residue are usually in great shape, just messy. Those I've acquired that have been dry or just barely oiled show a great deal of wear.
I'd rather clean up a messy machine than rebuild a worn out one.
OIL .... is your machines blood. Don't scrimp on it.
Joe