1. New friends like old, old friends like new.

解析：这句话直接表达了原句的意思，强调了新旧朋友之间的对比，以及新旧朋友都能成为知心朋友的情感。

2. New acquaintances can be as close as old friends, and long-standing friendships can be as superficial as new ones.

解析：这个翻译更加深入地探讨了新旧朋友之间的关系，暗示了人与人之间的友谊并不完全取决于相识的时间长短。

3. The closeness of new friends can surpass that of old ones, and the familiarity of old friends can be as fleeting as new acquaintances.

解析：这个翻译强调了新旧朋友之间关系的动态变化，暗示了友谊的深度和表面的熟悉度都可能随时间而变化。

4. New friends can be as loyal as old friends, and old friends can sometimes be as indifferent as new ones.

解析：这个翻译突出了新旧朋友在忠诚度上的对比，同时也暗示了老朋友可能会因为各种原因变得疏远。

5. New friendships can be as enduring as old ones, and old friendships can sometimes be as fleeting as new ones.

解析：这个翻译强调了新旧朋友在持久性上的对比，同时也暗示了友谊的持久度可能并不总是与相识的时间成正比。

以上五种翻译都保留了原句的意境和情感，通过不同的表达方式，传达了“白头如新，倾盖如故”这句话的深层含义。