I suppose one does acquire some skill over time in seeing things more readily, while one's physical abilities decrease.
On balance I am fairly certain that spending more time on an individual observation will help that observation, regardless of experience or cornea tint. For example, half the time any object spends above the horizon, its observability is improving as time progesses, all other things being equal, simply because the target is rising. More time also means increased odds of catching other favourable but more transient conditions such as good seeing or (for Melbournians) a hole in the cloud deck
Light pollution tends to decrease over the course of a night, the Moon might be setting, etc. etc.
So, I'd fully expect two people of equal ability to still take different amounts of time to log a marginal object unless they were looking through the same scope at exactly the same time, which would make for a rare and interesting sight!