If I take a few days off, and the shop is down in temperature, the initial firing of the tube does take a few seconds (5-15), I think the longest I had to wait was 45 seconds, but that was after a week of no use. Once it fires, it starts right away for the rest of the day. It's only the initial firing that sometimes takes a few seconds. My old tube Fired first time every time right up to the end. Even then, it didn't quit, it just had a big power drop off..