I had same issue :D work,family,social life keep me away from DCS.
So in my spare time I found this app very useful giving me time something different than the official manual and Chuck guide (if it possible!)
https://play.google.com/store/apps/details?id=com.threeappsstudios.mig21
If you read about aviation in your spare time you can study a module in depth, this cannot be done with any FC3.
It's a continue learning, forgetting,relearning process that I'm doing around Mig21,Ka50,Huey, my fav modules.