With regular maintenance you could get two or three years out of that mower without it starting to have issues that take up too much of your time.
Change your oil every 25 hours or at least on a weekly basis.
Change the blade regularly, do a complete inspection and tighten things.
The gears that turn the wheels get dry. You have to take the drive wheels totally apart. Clean things good with a wire brush or even really hot water with liquid dish soap and a wire brush. The grass and grease gets into the cogs and makes a paste that builds up over time.
You could clean the clips, washers, spring and other small parts in car brake fluid or some-thing similar. (carb. cleaning fluid?) Then every-thing gets greased up and put back together.
I spray any moving parts with WD-40 or fluid film.
I recommend that you purchase a spare drive wheel and a set of cogs, clips and spacers. (50 dollars?) The wheels have a tendency to loosen the drive bolt and you could lose important parts in the grass.
I watched one of our wheels take off down a long steep road....and the small parts rolled into a storm sewer grate.