In another related question: How to connect Einstein's Special Relativity (SR) with General Relativity (GR)? , John Rennie stated that SR is a subset (or rather can be derived from) GR, but not vice versa.
I've also sifted through other related questions on the stack, but it's still not clear to me that if a physicist is trying to calculate time dilation if both SR and GR have to be considered.
In other words do speed and gravitation independently have effects on time dilation?
Or in all conceivable situations can one just apply the field equations of GR and be done with it?
