You don't sight a shotgun otherwise.
You might not but I do... For a few circumstances.
I'd be inclined to take frugal shotgunner's with a grain of salt. Too much read theory and not enough real life practice. Personally, the only time I mount the gun is on target aquisition, then its point fire and pick up the dead shtuff.
While I may be frugal now, there was a time when I could honestly tell the walmart store that I wanted to buy all of the ammo in what ever caliber/gauge fit the latest new purchase...
And this practice took place ONCE PER WEEK!!!! 4 times per month unless there were 5 thursdays at which time it was 5 new purchases per month... AT LEAST!
Was fun to fill a buggy with a shopping cart of 12 gauge to go along with my new walmart purchased Mossberg 500 Bullpup!
And i would be low on ammo by sunday night as I threw shooting days every weekend possible for my "Club Brothers" and I bought the ammo used in my guns.
As for practice... you really are barkin' up a slick tree. Granted, I do not practice or fun shoot like I once did but it isn't just about the money... I am at a point in my life where 5 rounds pre huntin' season is all I need to shake the rust off myself.
During the year, I am a one shot killer of squirrels for Jr.'s pet snake which can easily handle 2 per week. As well, I am equally lethal on feral cats and other uninvited trespassing species. Why spend $.50 on 2 rounds when .25 for one can get the job done EVERYTIME?