It is sometimes amazing how we overlook the simple things. In my last few mountain bike rides, my bike was making creaking sounds like crazy. I had already replaced my cranks and I assumed that I needed to replace the bottom bracket. Well I thought before I replaced the bottom bracket, I would try cleaning the seat post and seat tube. Once I did that, amazingly enough the creaking stopped.
It makes me wonder how many times I overlook the simple things for a more complex solution and not just on my bicycle.