Let's directly go to the example. I am writing a sentence
Calling this function multiple times is unnecessary but harmless.
['Call a function' is idiomatic in say C/C++.]
I have a feeling that there could advantageously be an adverb placed at the end of this sentence to make it look more natural. But I am not sure whether it is
Calling this function multiple times is unnecessary but harmless either.
or
Calling this function for multiple times is unnecessary but harmless as well.
or something else.
Can someone please offer advice on this?