Woah, woah, woah. Kinda crazy and off base stuff here. This is a common question and there are dozens (hundreds?) of threads on this same issue.
The credit card companies do want you to use their card...and a lot...but only to the point where they think there is no risk. You start spending more than the average spender and they get scared. It's the outliers that cost the banks money so they are on high guard for that. Of course there is no magic number....it's a very complex formula and each bank has it's own philosophies on how they manage risk. I wouldn't be the guy to best explain that part.
The point in relation to this thread---You want to look as normal as possible---while increasing the spend as high as you might want for MS. My only hard and fast rule is always pay your bill and pay on time. Beyond that everyone has their own theory and strategy a little bit.
I will tell you that your spending activity has no bearing to how much money you actually have (they don't know) and mostly no bearing to how much money you make. But even making $33k per year you can mimic the spending amount of someone making 2-3x your income and raise no red flags. Whereas the banks don't have a good handle on everyone's income or assets---they have all of your spending habits on lock down. Tons of money was spent to develop credit reports and credit scores and banks rely heavily on this data. So when it comes to credit--make sure you manage your credit properly.
I hope this helps. It's late so it's not my most well written reply but it should be of some use.