Always the same - having an excuse for not tipping (10)
I believe the answer is:
changeless
'always the same having an excuse' is the definition.
I can't judge whether this definition defines the answer.
'not tipping' is the wordplay.
I cannot really see how this works, but
'not' could be 'less' (I've seen this in other clues) and 'less' is found within the answer.
The remaining letters 'change' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for changeless that I've seen before include "Consistent" , "Very steady" , "same as always" .)