Only if it is filthy. With some I might do it more often, ie. hunting loads or accuracy loads. I'm not sure if it helps enough for me to notice. We might be talking !/8 or 1/4" at 100 yards. I'm not a bech rest shooter or competitve shooter, so that small difference doesn't show up to me.
I used to actually clean primer pockets, but found it to be wholly unnecessary. Visually inspect to ensure the flash hole is clear and full, with no scale obstructing it in any way, then seat a new primer. Clean primer pockets are nice, I suppose, but serve no function whatsoever. Consider how turret and progressive presses work, and how great that ammo typically is, and you'll be forced to concede that cleaning the primer pocket is just pointless busy work.
For match ammo, the flash hole matters and the pocket should be uniform, but even there it doesn't have to be "clean". IMHO, YMMV, n' all that.
Mine only get cleaned if I am wet tumbling something ( pretty much all my rifle brass) but it is only a side benefit of the wet tumbler.
I used to clean them when doing rifle but they way I clean now it is a non issue.
Pistol brass I never clean except the 357 sig, which gets wet tumbled so they are clean in those.
The last time I cleaned a primer pocket it was to show a guy what I used to do when I first started reloading. I couldn't begin to guess how many years its been since I did it for a round of reloading.
I clean mine ever time does'nt take long and I'm sure the primer will be seated fully. I heard a long time ago it was'nt necessary, but it's an old habit now...
I clean the primer pocket, uniform the primer pocket, and flashole debur on each and evry case I reload. It is all about how OCD you want o be when it comes to your reloads. Of course, after doing all that work, and some friend pops off ten rounds without seriously trying to do their best, I get all bent out of shape..all that work for nothin! lolz
I watched a guy reload 6PPC rounds AT the shooting bench, never cleaning anything, and he was shooting groups that were 1/2" or less. Pretty brass is nice, but the gun doesn't know the difference.