Used to express a preference or wish that something be done if possible; 'preferably' or 'if circumstances allow.' Common in conversation.
なるべくなら来週の会議は避けたいです。
If possible, I'd like to avoid the meeting next week.
なるべくなら早めに返事をください。
If possible, please reply as soon as you can.
環境のことを考えると、なるべくなら車は使わない方がいい。
Considering the environment, it's better not to use a car if possible.