I applaud you for taking such good care of such a cheap bike
Are you upgrading somewhat the parts that break down? Or replacing with similar quality? By upgrading slowly you may end up with a decent bike without a large one-off investment.
Comparing your bike with what a lot of people around here ride, many of us have the privilege of being able to buy $1000 - $2000 bikes, just isn't fair.
1000 miles is maybe what I'll ride in two weeks or so on tour. I expect any wear and tear in that time to basically be unnoticeable.
i tend to replace with slightly improved but still cheap parts. the reason that i ride such a cheap bike is because of the high level of theft round these parts. it almost broke my heart last time my bike was stolen
i actually really like working on my bike, i've learned to fix most problems just from having a bike that breaks all the time. i don't think that i would have been brave enough to do maintenance on a high end bike but now i have plenty of experience.
i'm actually going to upgrade for christmas i think. i'm looking at a merida or a giant moutain bike, still cheap but a noticable improvement is quality and performance. can't wait!