After two more drinks, you'll be shocked at how good you've become :-)

The mind is a powerful thing

A common experience for musicians of all kinds, I think. There are benefits to taking periodic breaks, for your brain to process information and your body to rest. But part of it is also perception... When you play every day, you get tired of hearing yourself. Things sound fresh after some time away, even when objectively speaking there may not be much difference.

For sure. Our brain continues processing(?) new information when we’re not directly engaged with that new demand being made of it. I’m not a scientist or neurologist and I don't know the terminology and can’t describe the biology. But the evidence presents itself and is fascinating when we become aware of it, and experience this wonder of nature functioning in this way.
I’m currently learning a new tune with, for me, an unfamiliar 4-note chord requiring my left-hand fingers to find a completely new shape up the neck. At first uncomfortable, clumsy and slow is becoming comfortable, quick and ‘automatic’. This progressive improvement between practice sessions can only mean that this motor skill is being developed while I’m away from my banjo, using the input from my practice repetitions.

When we are aware of this 'remote' processing we can trust to it and deliberately use it to our advantage. It is a process that can also be used to advantage to more efficiently memorise tunes.

When I was first learning to play guitar, many years ago, I could not get my fingers to do a barre chord. I struggled for quite some time, and eventually gave up and didn’t play guitar for about a month.
I came back and picked the guitar up, and suddenly I could play barre chords.
Not sure how that works, but it worked

…to be specific in regard to exploiting this process to increase efficiency in memorising a tune - deliberately use that ‘remote’ processing capacity. Note: this is not learning how to play a tune, but a method of rapidly memorising a tune that we are already technically able to play.

Method.

1. Play through the tune (or section of the tune, slowly, cleanly and accurately from notation once.

2. Stop. Put your banjo aside.

3. 1-4 hours* later play the tune again using only memory recall. There will be omissions/errors. Play the tune again once from notation slowly, cleanly and accurately. Stop. Put your banjo aside.

4. Repeat #3 as necessary.

This use of our brain’s remote processing is hands-down more efficient than simply endless machine-like repetition of a tune.

*- this time-lag duration is individually critical. We are all different and need to find our own optimal 'lag' duration. Too short, and we are simply relying on short-term memory. Too long, and we lose the information. This method efficiently and quickly sets a tune in long-term memory where we need it.