In terms of increased marksmanship proficiency most ammunition expended by civilian and military folks is largely wasted.
Most military personnel are not marksmanship enthusiasts, go to the range by order, and are lead through staid courses by other non-marksmen. The concepts of the course of fire are often lost due to being interpreted by personnel who may not have ever read the appropriate Field Manual or regulation directing the training.
Outside of the competitive realm civilian gun owners don't even have this much. Hunter's Education and basic safety courses are the limit of most gun owner's knowledge.
If you like to plink, please, have at it. Some people just like to hear the gun go bang. If your goal is to have fun and you can discharge firearms without injury or damaging property then have a good time. Just don't pretend that such random activity will somehow convey good shooting skills.
Ideas to help you Stop Wasting Ammo:
Conduct regular dry practice
Train in dry practice, test with live fire
Shoot with a plan
Make use of sub-caliber arms, such as air guns and .22