My first laptop lasted 6.5 years, but barely. I think it was poorly built, the heat became intense enough to ruin the keyboard. I still use it occasionally with an extra keyboard.
My current laptop is 3.5 years, and as good as new.
I think if you want your laptop to last awhile, you need to futureproof it some ways. While all these updates for various browsers/ OS/ etc. are designed to work for all computers, they work best for higher spec computers.