One very interesting statement that I read in Peter Lynch's book: Owning stocks is like having children. Meaning we should only buy as many stocks as we can handle, especially for those part time stock holders. Because, it takes time, patience and effort to manage each one of the stocks. Even if it means that we only look at the annual / quarterly report every 3 months. But still, that takes time.
Personally, apart from the annual and quarterly reports, I usually will search for any potential risk that the company might face on a regular basis, especially when it comes to a company that has debts, it's important to know that they are still able to pay off the debts and not end up in bankruptcy. For such cases, usually you will see a notice in the SGX announcements or even just the regular news. When the red light indication is on, you just need to be aware and careful about that particular stock you are holding. Because, it might be just between 2 weeks to a few months that the stock can get suspended from trading and there goes all the hard-earned money...