My Shihan has said to us that if you want to learn Aikido as an interest and for health then practice many techniques and work on both sides of the body. Thats okay.
If you want to learn Aikido as a Budo then train one side of the body only and work on fewer techniques to perfection. Unless you have the luxury of training all day every day most of us will not have enough time to become proficient enough to apply Aikido at the level needed to survive a real serious fight against another trained fighter.
My Shihan just teaches. And very well at that.