I also work at a similarly large company. Some of our internal infrastructure systems are 10-20 years old - some could definitely do with a complete rewrite, b

I also work at a similarly large company. Some of our internal infrastructure systems are 10-20 years old - some could definitely do with a complete rewrite, but in the meantime, they're mission critical systems. As for our products - some of them have even longer timeframes than 20 years.