Every year your lawn creates about a hundred pounds of nitrogen per acre. That is over two pounds of nitrogen per one thousand square feet, which is about two fertilizer applications per year.
It is estimated by many experts, that up to 60 percent of the fertilizer applied to your lawn is removed by removing the clippings.
When you bag, you are removing a significant amount of organic matter from your lawn.
The money saved can be substantial if you have a large lawn.
Now, there is work involved, if you wait too long between cuttings, the grass could grow so much that the cuttings do not break down quickly, but I know, if you are reading this, that you are interested in creating a healthy lawn, and would never allow that to happen. Mowing frequency is a big part of good lawn care, and on most of our grasses, the more frequently you mow, the better the quality of your lawn. This helps in a couple of ways:

It makes the clippings easier for nature to break down into nitrogen.
It causes the grass to grow laterally, thus getting thicker, and filling in the empty spaces, or as we say, it “tightens the turf”. This makes your lawn more wear tolerant.
I hope you will give this consideration when the time to begin mowing arrives. It is the most ecological, economical and aesthetic way to a better lawn!