I was told to always pay every credit card in full every month if I could as it would help my credit. So I have done, every month.
But this month I let two of my cards report a small balance as I honestly just forgot to pay it all.
Both cards reported roughly $50.
My EX jumped up 18 points and the others roughly 10!
Does anyone know why this happens? Should I be doing this every month?
Very happy 
@Anonymous wrote:That's a great question, buddy!
For many years, all that the CRA databases recorded (as far as your credit card balances and payments) is what your most recent balance was and whether you were "paying as agreed" -- i.e. for a typical credit card, had you made at least the "minimum" payment. If you had missed payments in the past, or if you had been late, they would capture this kind of negative infomation in painful historical detail. But if there was nothing negative, then the details of your positive payment history were erased after each month, e.g. exactly how much did you owe on your Amex six months ago and of that bill how much did you pay?
That was until a few years ago. TransUnion started recording for credit cards the exact amount that you were billed each month, and of that month's bill how much you paid, not for many years of history but certainly for many months Prior to that FICO could never have asked in their models the question: does this guy PIF each month or does he sometimes pay less and carry a balance? The CRAs simply didn't provide enough data for a credit scoring algorithm to distinguish between the two.
I am pretty sure that FICO does not do that in any of their models, not even the latest FICO 9. But that doesn't mean that they won't in the future. In fact, I personally think it is likely that they will, now that CRAs have started capturing it, since people who carry balances have been shown to be a good deal riskier as a whole than those that PIF. Just another reason I personally think it is good to get in the habit of PIF-ing.
Experian > TU > EQ looking at my old reports in terms of rollout of reported payments from a trivia perspective.
FICO is blind to the payments currently, and not all lenders report it (Amex notably does not). As a result doesn't effect score, but if it's on the report it can be used by an individual lender to make a decision. I hope in the future that all lenders do report it, and that FICO makes use of it, as the $0 all balances penalty is pretty lame when looked at rationally from a consumer perspective as indicative that they aren't using their cards at all.
@Anonymous: Having $50 report every time is fine though unless you're stressing about it it's hard to make a file report identically a single balance each time if you're using the cards normally and really not worth it. The one caveat I would suggest, use some other card than one of your Chase ones for reporting a balance... Chase has a recent policy where if you pay off your balance to $0, they do a mid-cycle report flatlining that card's balance. It's a small gotcha if you aren't applying for anything, but it's something to be aware of if we're talking FICO maximization at instant-in-time for just what you found earlier, might have all your cards reporting $0 which is a non-trivial penalty.
