When we take extended trips, I keep track of how much we're putting on the credit card and pay it off a few days before the due date using online banking.
We try to use the debit card as much as possible though so the $$ are paid direct rather than being charged.
Utility bills are sent to me via email and I pay before the due date. Only one utility bill now comes in by mail, so I guesstimate that one and pay a bit more than I figure is due.
Because we now live in the bush with a GPS coordinate for an address :B I rely on online services much more than in the past. Works great for travel too.