A computer monitor lasts between 3 years to 10 years depending on how much use the computer monitor gets.
The more the computer monitor is on the shorter the lifespan it will have.
I usually get 5 years to 10 years out of most of my computer monitors and actually I still have a LCD computer monitor from 2005 that I use on a second computer and it works great still.
So that HP LCD computer monitor is almost 16 years old and still going strong.
Last year I bought an onn brand computer monitor from Walmart in the store on sale for $85.00 and it's been working great for me so far.
If I get a few more years of use out of it I will be happy but I expect it to last at least 5 to 8 years before it does go bad.
If it does it's cheap to get another one.
I'm using the onn computer monitor right now and it's a very good computer monitor for the price.
You can also buy higher cost computer monitors that may last longer and give a better picture especially for gaming.
However I just work from home, browse the internet and the cheap computer monitors are good for me.