I just upgraded my accounting system at work accept terminal server clients. This upgrade allows my employees to deny NET terms by checking into our accounting records from deadbeat's office internet connection <g>
Did Bat Mitzvah 2 yrs. ago. Paid the caterer and the DJ a couple of weeks in advance, but did so by personal check. Nice part about that is you are enjoying the simcha and taking care of your guests instead of writing checks. These folks depend on repeat business and will not stiff you. That same DJ and caterer will probably work two or three other bar/bat mitzvahs in your daughter's class alone. The caterer should be able to invoice any unexpected items (e.g., heavy bar tab) after the affair.