How often do you clean your guns?
I don't own any guns :-X
After every use?
I believe this is the best practice to get into, it takes a short time and assures you that the gun was taken care of properly and will work the next time you want to make a range trip as well as the fact that it keeps them in tip top condition.
Every few months?
this one may be for things that don't get shot often, I think once a year or every 6 months its a good idea to take a look at the things that are just sitting in the safe just to make sure rust isn't creepin in on anything, besides it gives you an excuse to pull the less used ones out and take a gander
Every other use?
this can work and in a lot of cases will be good enough, but I prefer the after every use.
Is it necessary to clean after every use?
what do you do when you get dirty? ya take a shower right? (I hope lol) ;D necessary? nah, but its a good habit to get into, that goes for the shower too!
I clean mine after every use, even if I only shoot 1 magazine through it. Is that ok, or is it overkill?
I don't see it as overkill at all, its yours, take care of it to whatever level makes ya comfy. it can never get too clean so no worries there 8)
The views expressed above are not to be taken as anything but a humble opinion by a non expert, and you know what they say about opinions, they are kinda like belly buttons