Just don't let the tube show a single digit for too long. It would probably wear it out more evenly if you make the numbers "blink", e.g. instead of always show

Just don't let the tube show a single digit for too long. It would probably wear it out more evenly if you make the numbers "blink", e.g. instead of always showing 3, show "03" by alternating between 0 and 3 with a longer delay after showing 3: 0 .. 3 ... 0 .. 3, etc. (like the bulb clock actually works https://www.daliborfarny.com/product/blub-clock/ https://www.daliborfarny.com/product/blub-clock/)