How to reduce size of "messages" storage?

You must manually delete your old messages.

There is a rumor that iOS 8 will include an option to auto-delete old messages after a certain period of time.

 

I usually delete all conversation once every 3-4 weeks.
No need to save them and take up room for nothing.

 

You can generally go conversation by conversation by sliding to the left on each one and selecting delete.

 

Swipe left on each separate conversation to delete.

 

I'm going in the opposite direction of this thread, but is there a way to save messages in an easy-to-read format?