Schedules are hard to find in the Philippines and not always reliable. Ceres Bus liner, the biggest in the country, provides regular busses between almost every city and barangay in the Philippines.
The point is to find the right and most comfortable bus. Going with a regular bus can be a fun experience and you meet a lot of locals. Windows open, chickens on board. But also a stop at every corner and little to no comfort.
In between the bigger cities there are air con busses riding back and forth. They offer more comfort, there is a video on board for entertainment and many offer free wifi. Some even have on board CR.
There is not much price difference between liners and local busses. So if you travel a long distance, maybe an air con bus is a good option.
Cost break down, stops and the rest of the route between Dumaguete and Cebu you can find in this post
Time tables air con busses between Dumaguete and Cebu and v.v.:
|Departure Dumaguete||Departure Cebu|
|3.15 AM||6.00 AM|
|4.15 AM||7.00 AM|
|5.45 AM||10.00 AM|
|8.20 AM||11.30 AM|
|9.15 AM||1.00 PM|
|11.20 AM||2.30 PM|
|2.15 PM||4.30 PM|
|10.30 PM||6.00 PM|
Please note that schedules may change due to weather, breakdown of materials and because busses and or ferries are not full. You can always check with a dispatcher in the bus terminal about changes.