第二个 of 可以省略。但不省略 of 会显得更严谨：

The best portion of a good man’s life is his little, nameless, unremembered acts of kindness and of love.

一个好人一生中最美好的部分就是他那小小的、不为人知的、默默无闻的善良和爱的行为。——威廉·华兹华斯

类似的例句如：

It was a matter of life and (of) death. 那是生死攸关的事情。

Are you coming on Monday or (on) Thursday? 你是星期一来还是星期四来？

Do you prefer traveling by train or (by) bus? 你比较喜欢坐火车还是坐汽车旅行？

He is either in Malaysia or (in) Indonesia. 他在马来西亚或者印度尼西亚。

Was the Mona Lisa painted by Michelangelo or (by) Leonardo da Vinci?  蒙娜丽莎是米开朗基罗画的还是达·芬奇绘制的？

但如果介词不同，自然不能省略。如：

Are you paying in cash or by cheque? 您付现款还是付支票?

The bill may be paid by cheque or by credit card. 账单可以用支票或信用卡支付。