I had a Dj that worked with us a while back. He had a rough transition to computers. I spent hours showing him things. The problem was he wouldn't remember when it happened a year or so later and we were back to square one.
I showed him how I maintained a number of computers. Rotated them so I knew they were all ready if I needed them to be a show computer.
When his computer would fail, he'd always be telling me how it wasn't his fault. I would tell him it is because he he just finding out about it before his event. He wouldn't use his computer between events enough to get comfortable with it or to know is something needed fixed.
"Crap happens". Plenty of things happen that are beyond our control. Being ready for these things is a simple sign of maturity and experience.
I did a small karaoke show last Thursday. I rarely do karaoke any more. I tested my computers and they worked fine. However, at the event, I wanted both screens to show words full screen, something I didn't test. On the first computer, it didn't work, would only do either/or, so I switched to back up and show went fine. I will research and find out what happened, but the show went perfect because I was prepared with backup options.
No one is perfect. I made the mistake of not testing exactly the way I wanted the show to go. But because I had plenty of back up options, customers never saw the issue I had.
We all make mistakes. I've made tons. Mistakes can be great lessons IF YOU LEARN FROM THEM... AKA not doing it again and again. But if you make the same ones over and over, it says you don't like doing it enough to get better at it.
That's what I told the guy that worked with us. "I dont feel like you like doing this enough to get better and comfortable with computers". Going back to CD's wasn't an option.