From the early code snippets of the first chapter up to these final recommendations on the behavior of subscriptions and disposal, you now have all the keys you need to implement functional and reactive applications that are readable, extensible, and robust.
The creation decision tree (list) is very useful when you are not fully at ease with all the available operators. Even after some time, it is a good idea to go through it again to avoid the tendency of always using the same operators even when more appropriate ones could be used.
It has been explained previously in this book but it is worth reminding you here: side-effects should be isolated from pure code, and their footprint should be reduced to the strict minimum. This often mean splitting some existing code into several parts, but this additional work is usually rewarded quickly with code that is easier to test...
