I just came in on a TR60 visa, valid until 25 January, I will be leaving on the 14th of January.

I wonder if I do an extension, can I save the remaining time for when I come back to Thailand.

Reason: I'm staying in the South of the Philippines, Cebu honorary consul does not issue Visa's 

I don't like to have too many visa exceptions in my passport.

Thanks for the enlightment

You can’t “save“ days; just protect a previously granted stay.

 

If you extend your stay it will be until 24/02/20.
 

When you leave on 14/01/20 you would need to buy a Re-entry Permit (1,000 baht). You would need to return before 24/02, and whenever that is, will be stamped in until 24/02.

 

An issue may be applying for the extension on or before 14/01 which will be 10 days early. Most offices should do it, but they might not.

El viajero, muchas gracias