I bought my MacBook Pro in 2014. It’s still running fine generally although the battery wears down quicker now of course. I don’t get notice of automatic updates anymore so haven’t updated the operating system in a while. I assume that’s ok?
I will probably wait a few years to get a new machine. When do the M1 updated versions come out?
Avoid public WiFi hotspots or Guest networks. Not saying you'll be totally safe, but safer. As it stands, a six year old computer that's not fully patched on a public WiFi is like a kindergartner being offered free ice cream if he'll just climb in the back of the ice cream truck.
