+2
I remember being laughed at for the corn cob tumbler in the 80's, by people with really ugly brass that would hold their 1911 with one hand and make one hole groups pretty much all the time.
I often don't even clean my revolver brass for 2 or 3 reloadings, and then it is just dry corn cob. My indoor range brass gets tumbled most, but not all the time. Brass that gets picked up out of the sand/dirt gets cleaned before I size them.
I have many friends that retumble the lube off rifle brass after sizing. I do not even do that. I use very little lube and drag a rag across it when I put it in the box.
If having your brass shiny inside is important to you and makes you feel better, it is a good thing to do.
Depending on the quantity of rifle brass I'm loading at the time, I often skip the 2nd tumbling, as well.