That "running total in your head" method will get you in trouble! My oldest brother keeps track of his money to the penny, and I mean he keeps track of how he spends it, to the penny! He's sort of pressuring me to do the same, but that would drive me crazy.
Dot,
I put nearly everything on just two credit cards. I use their money for a month, get cash back and can go online anytime to find out balance. Additionally, if I have a problem with purchase I can always stop payment thru card company. They'll take if off the bill while they investigate. When I go out to eat, I pay cash as there is no sense in spreading my card information around. (Most firms don't do background checks on the waiters.)
I keep a check register, but mostly for backup. I also get all bills electronically and thru post office. Never know when the internet is going down or my computer is going to crash.
The one bill I do write a check for is the mortgage. I want to keep it at the forefront and ensure I pay the extra principle.
Bob | 
