I believe you should practice, every chance you get and at least daily. One of my favorite things to practice is repetitive patterns or melodies. The more you do it, the more your muscle memory function gets better. However rest is just important. I noticed that I start to make errors if I practice the same thing for too long without any breaks. At this point I like to go away and do something else away from that particular room. There are times when I have switched over to the PC and starting watching YouTube, Facebook etc, or even movie. I found that that does not really help and it is not adequate rest. I think you need to stand up, leave the room, do a completely different activity, even take a walk and then return to practicing later on in the day.
People say you don’t get better overnight, however I believe you do. Good solid practice, followed by overnight rest allows you to play that little bit better than before because you are fresh.
Stuck in your comfort zone
Most people tend to hit a plateau and then become very discouraged with their instrument learning. A lot of the time it is due to the fact that people are hesitant to come out of their comfort zones. Some can be hesitant to take on new challenges that will ultimately improve their playing. I remember always avoiding learn the 7 chords for each key Major and Minor for a long time. It actually made it difficult to play in bands especially if a key change was required. Learning these chords improved my playing by leaps and bounces, as I was able to play along to songs easily once I had identified the key.
Live performances and recordings also improve your playing because you are under pressure to get it right.
Also try to play in all keys especially for the piano or keyboard. Guitarists can make adjustments to change keys but piano player must learn the different scales and chords. Many people tend to avoid in familiar keys. Knowing all keys helps you to play “borrowed” chords which is essential for the R&B, Jazz or Neo Soul genre.
Back to the basics
Never think you are too good to brush up the basics. Many people are stuck on the an intermediate level but think they are too good to go through basic exercises. These drills, fingering, strumming etc. are the foundation of your playing, they must be covered even in you practice sessions. Timing is also essential. If you are recording time is waste with multiple takes if you timing is off.
I remember I used to play something to record and then manually adjust the notes if they were off time. I would do that by recording MIDI and Audio simultaneously. I would then mute the Audio and have the MIDI play back through my keyboard with manually adjusting the notes. I found this to be extremely time consuming so I practiced by timing a lot better.