200
Why OLED monitor burn-in isn’t a huge problem anymore
(arstechnica.com)
This is a most excellent place for technology news and articles.
Not OP but my electicity is <$0.10 / kWh because of where I live. It seems like it would take much more than 13 years to hit the break even point on upgrading the monitor just because of energy efficiency.
Even if the newer monitor has less of a lifetime environmental impact, throwing out the old still working one is still wasteful. It's already made and working. Using it longer lessens your environmental impact. If you repair the old one when it eventually breaks, that's still less of an impact than an extra ~20% electricity usage. Especially since electricity generation is getting greener all the time.