It would be great to have some more relevant info in the ticket screen, or even ticket creation screen.

1) Other open tickets from the same customer.
2) Recent closed tickets from the same customer
3) Open invoices from that customer (possibly with an alert if they are aged)

Sometimes techs open a ticket for a customer and start helping but probably shouldn't if the customer is being bad about paying for past support.

You can provide better support if you have a snapshot look at the most recent support issues as well. Maybe there's a pattern, maybe the customer is crazy. Right now I do manual lookups on every single new ticket to see if there is any recent service history.