For instance, my wife and I recently redid an entire small bathroom. I replaced wallboard, replaced toilet and cabinet and sink, and laid tile. I'd never done any of that before.
It was incredibly scary at first. But I finally said, "What's the worst that can happen?" We paid a plumber for the hard stuff like moving the shutoffs and replacing the cracked flange (my fault!) and did the rest ourselves.
The worst thing that could happen was that we damage something (which happened with the flange!) or that we decide we just can't do it to our satisfaction and have to pay someone.
The alternative was to just pay someone.
In the end, it was still scary, but it was the logical thing to do, and so I tried it.
It went very, very well. Except the flange.