I bike commute 28 miles most workdays year-round and have been doing it now for more than six years almost entirely on the same bike, a 2010 REI Novara Randonee touring bike. At this point I estimate that my go-to ride now has somewhere north of 20,000 miles on it, so it needs some regular bike repair. It’s an interesting case study for what lasts, what doesn’t, and which components need replacement over time.
Several components have stood the test of time. (While the specific components originally included with the bike are no longer available new, I have listed them for reference.)
In terms of ongoing care and maintenance, I confess to being not the most vigilant. I do lube the chain every two to four weeks for a smoother ride, depending on riding frequency and conditions (Finish Line Wet is my go-to), occasionally hose down the bike if it gets really dirty, and every once in a while will clean all the gunk off the jockey walls (those two small gears in the rear derailleur), which can get quite thick. Otherwise I just ride, ride, ride, and replace the things that need replacing when their time is up.