My daily cycling mostly consists of a mile and a half to the station each way without any serious hills, but my station bike is one we got second-hand for my brother when he was a teenager back in 1980 or so and we repainted it back then, so it's probably over 50 years old. It is the scruffiest bike in the bike shed at the station, which is just the way I want it. But most importantly, just about everything on it still works. It was once a racer with a lightweight steel frame, but I put straight bars on it 20 years ago. It lives outside year round and has done so for 25 years, so it has a nice patina that means thieves always look the other way. A little rust converter every now and then ensures the corrosion looks much worse than it really is. The original pedals finally fell apart a couple of years ago, but replacements were readily available. The front derailier failed and I removed it, so it's a 5-speed now, but that is fine for my use. The saddle has been replaced many times. And the rear wheel needed replacing twice. But it's still on the original chainwheel (!), brakes, rear derailier, shifter and remarkably, front wheel. Headstock bearings and bottom bracket are original too. Anytime I have needed something, the local independent bike shop has it - all the parts are still available.
Alongside it at the station are so many nice looking bikes, but chances are mine will outlive all of them and not get stolen either. Anyway, if you're getting a bike as transport, get yourself something used from way back that was a high quality bike back then. Some of them at least were built to last, they're easy to repair, and are still way lighter than most modern bike shaped objects.