I was away from the cockpit for a long time, and jumped back into it this year. The flying skills and scan came back pretty quick. The hard part for me was procedural, remembering when to do what and doing the little things to stay ahead. There were several moments when I knew I should be doing something, but kind of just sat there wondering what to do next. It took a while to get comfortable with my habit patterns, but once I did I was back to normal.
As for omitting the AI in the scan, everybody has their own way of doing things but I would advise against it was unless your scan just naturally leads you to that point. I like to scan what is going to give the first indication of deviation. My primary scan revolves around AI, and VSI. For wings level, I scan the arrows at the top of the AI. To hold altitude, I primarily scan the VSI and my secondary scan is to my altitude indicator.
When you get into the terminal environment, you will have to scan your AI for turns, establishing descents, and other things. I would not want to change my scan from what I had previously been doing during the cruise phase once I get busy in the terminal environment. I would prefer to use the time at altitude and wings level to build that habit pattern that will be useful when things get busy. When things go wrong, the AI is your best way to keep yourself safe and get back in a good position. I personally think it's important to keep it in your scan, but I know different things work for different people.
