I have used PSOs and PSCs pretty regularly. Sometimes I'll skip the application & go right to lather. When I skip any oil or cream, with milder razors I don't notice much difference in overall 'feel' of the lubricating qualities. But when I use the more 'hyper' aggressive DE shavers— such as the R41 & Futur—the difference a bit more lubrication and protection is distinctly noticeable. With a straight razor, it's night and day—at least in my limited SR experience. The 3" blade glides much easier and my skin always feels 'better' when I have applied a good pre-shave oil or cream.