On the beat and on the dot?
I believe the answer is:
intime
'on the beat' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for intime that I've seen before include "Eventually, sooner or later" , "Early enough" , "'A stitch .. .... saves nine'" , "Eventually or not late" .)