Bicycles, like anything else mechanical, require periodic maintenance, based on both miles and time. Rubber dry rots, grease hardens, metal oxidizes. This is just the realities of the world. Is there a bicycle that you can jump on and ride 1,000 miles with only putting air in the tires? None that I have found in my 58 years on this third rock from the sun. Even if you don't ride on gravel paths or off-road, dirt gets on your bike, and when it meets metal, it is like grinding grit that wears moving parts.

Much like an automobile, a bicycle requires regular maintenance. The quality of bike you start out with, how you ride it (think things like "bunny-hopping" curbs here) and such are all going to have a bearing on how frequently you'll need to maintain things, but even a bike hanging from hook in the shed or garage deteriorates with age.

Remember too when buying replacement parts, that what you spend up front may have a bearing on durability. Those ten dollar tires may seem like a bargain until you discover that every ride includes a stop for a patch or tube swap out. The more complicated the bike is also has a cost effect. Front suspension may be way cool until it stops working as designed. In this respect, the simplest quality design that gets the job at hand accomplished will be the best bike for you down the road.

You ride on the street, and maybe an occasional excursion on a path? A full suspension, downhill bike, with all the bells and whistles is expensive overkill that will cost in added dollars and hours of maintaining it. Of course, the opposite is true as well. If you are an X-Games fanatic, spending your time trying to jump park benches and picnic tables, a lower end hybrid is going to get torn to shreds and become a maintenance nightmare.

Hope this helps provide some answers. Good luck!