Yes, you need to rotate house plants in as much as they tend to have unidirectional light (unless you live in a greenhouse). This will promote an upright growth habit as versus one that leans towards the light.

As to the direction of rotation - False. The same person who came up with this suggestion also was the one who suggested that if you wanted an "A" on an exam, you should walk twice around the building in which it is given, once in each direction, while chewing a raw red onion picked at midnight the night before.

It makes no difference how they are turned.

Many plants have an adaptation that causes them to grow towards the light. As a result, in order to keep them symmetrical, they have to get light from all directions, so they grow out in all directions.