My tablet pen died mid-stream and I almost deleted my whole portfolio

Last Thursday I was doing a live painting demo on my old Wacom and the pen just stopped responding right as I was shading a portrait I'd been working on for three hours. The battery was fine, the driver said connected, but nothing moved on the canvas. I ended up switching to a mouse and finishing the piece in a really janky way, but the whole session felt off and I was embarrassed for the people watching. Later I found out the nib had worn down to almost nothing and it was catching on the screen surface, which I should've caught weeks ago. It got me thinking about how much I rely on gear that I never really maintain, and how different digital art is from the old days when I just had paper and a pencil. I replaced the nib and it works fine now, but I'm wondering how many other folks out there have had a tool fail at the worst possible moment and what did you do? Did you have a backup plan or did you just roll with it?