This is from a guy that makes his living repairing computers and I listen to him. The main killer for laptops is heat. The cooler you can keep them running the longer they last. Set them on a hard surface or better yet when you are sitting around with it on your lap (since it IS a laptop
) use one of the fan cooled desks available just for that.
My wife's laptop sees a lot of use because she plays a lot of games. It's a HP that's over four years old now and that's the advice she follows. It's never had an issue, period. Free Avast is it's virus protection and it's never had a virus and you really don't know it's there except when the little screen pops up to tell you it's been updated. We have been using Avast on two laptops and two desktops for over two years now without one problem.
I have another laptop, a Gateway that's over 10 years old now. It was the wife's gaming computer until she decided she wanted a more powerful one. Other than a broken hinge which Gateway fixed free even though it was out of warranty it's still going strong but doesn't get used much now.