I don't normally count miles either. That said, I've logged 11,000 miles just around town over the past 3 years. I had to electrify my bike in November of '16 and that console included the first odometer I've ever used.
I agree with KC and Andrew above. A bike is just a group of components that get replaced individually as needed when they wear out or when you want to upgrade.
My current frame is 25 years old and going strong. I had to retire a previous frame after 12 years due to a rust hole at the top tube.