Is it necessary to repeat に in the following sentence?

Question

I gave my wife a mobile phone at Christmas.

私はクリスマスに妻にケータイをあげました。

Now there're two "に" in the sentence. Any method to avoid repetition? Is it necessary?

Answer 1

Although you appear to understand this, I'm still going to say it for beginners' sake: these two にs are indicating two different things.

The に in クリスマスに is indicating the time the action took place.

The に in 妻に is indicating the receiver of the action.

There is nothing unnatural about this kind of repetition. However if you really wanted to say the same thing without any repetition, you could say something like:

私はクリスマスプレゼントとして、妻にケータイをあげました。