I've heard from some people that "always" and "all the time" are not always interchangeable. I have written down a few sentences below.
(1a) Tom always writes novels at this table.
(1b) Tom writes novels at this table all the time.
(2a) They always go to math class with advanced calculators.
(2b) They go to math class with advanced calculators all the time.
(3a) I always enjoy working with you.
(3b) I enjoy working with you all the time.
In my examples, I think (1a)/(1b) and (2a)/(2b) mean the same meaning in their pairs. My non-native speaking friends think (3a) is OK but (3b) is wrong.
What is your opinion?