WordPress Plugins: How Many Is Too Many?

After talking about the Crazy, Scary Call With A Client, I had with a client where her theme basically blew up, wrecking her whole site, I started getting messaged with loads of questions about plugins like these:

▪ What plugins should I use?
▪ What about page builders?
▪ Should I learn to code and just avoid all plugins?
▪ How many plugins is too many?

Your questions were really good and I wanted everybody to be included in the answers. So, rather than answering everybody one-on-one, let's get together and talk about it. So here it is.