Tip your servers
Tipping is customary in the Philippines because of the low cost of services. It's traditional to leave 10-15% of your final bill at restaurants, unless service charges are included, in which case less is fine. The 10% guideline also applies to salons and spas. It's also typical to round up cab fares, for example, providing a 100 peso payment for a 90-peso trip (for app-booked cars such as Uber and Grabcar, however, the exact amount is usually given).
When in doubt, tip according to your level of satisfaction with the service. While waiters, masseuses, and tour guides will not be offended if you don't tip them, keep in mind that these workers in the Philippines are paid minimum wage, so a little goes a long way.