On 38 and 45 cases, I use the Lee "toothpaste tube" resizing lubricant and lightly lubricate every fifth case. After resizing, I tumble all the sized cases in walnut media.

The carbide sizer is a ceramic so it has some porosity and those pores hold on to the lubricant from the first case for several that follow. For me, five seems like a good number. If you have a heavier or lighter hand with the lube, you may have to go every third or every tenth.