Originally, the Philippines had a non-tipping culture — but it has become increasingly common over the years. Nevertheless, tipping is not always expected NOR are you obligated to do so. It's only more prevalent in the more touristy places of the country; but, as a local myself, I rarely leave a tip especially when the bill already includes a service fee. If you're rather feeling generous, anywhere between 10-20% of your total bill is fine.