Temple celebrations occur for many possible reasons. It could be the temple's anniversary or a traditional holiday for that temple's specific god. Most of the time, I find out about the street festivals as they occur. I pass by and ask a local attendee what the occasion is. Sometimes they might not even know! Still, there's rarely a good reason to turn down a chance to see the celebration. It's also an opportunity for younger people and foreigners to learn more about traditional practices. While the newer generations aren't as attached to these religions as their grandparents, many still pay respect to it as a part of their culture.
In older East Asian societies, temples were used as the center of the neighborhoods. Most city gatherings took place there, and travel was organized around their locations. Even today, large temples are popular stops for buses and subway trains. The city of Tainan (where I live and go to school) has the most temples out of any other city in Taiwan. It used to be the capital before Taipei, so it makes sense that they had many temples since there were many different communities and most traveling took place on foot. These days, temples tell stories of the history of a community through its architecture. Buildings are well taken care of throughout the years in order to preserve the statues and paintings made there.
