Emacs: defer or not?
If you start with plain emacs it will start very fast. More or less fast enough for you to not notice it. And for every plugin you add it will become a little bit slower. Some plugins contribute more to it than others. There are basically two ways to deal with this. Either to just let it load everything when you start Emacs or do defer it.
When you defer you either tell it to wait to do it after Emacs have started, or do this at a certain event.
I have tried many different combinations over the last year, and I have landed on not doing anything at all. The same kind of CPU time have to be spent no matter what you do. And I’d rather take another couple of sips of coffee while waiting for Emacs to load than to having to wait in the middle of something for something to load.