At some point in time, every one of you will need a full-time AR person to contact customers, follow up on problems, converse with sales personnel, send documentation, keep track of lien dates and finally get permission to send accounts to collection. Pay plan incentives need to be tied to the total AR balances and balances that fall beyond 90 days from the billing date. Monthly collection goals are also a must. Of course, management needs to monitor these activities to determine if the approach is too strong and is costing the company business. Conversely, if the sales team is involved you will hear about potential problems.
Placing a lien on a customer's job is quite often necessary, and the collection staff is responsible for tracking these dates. And when necessary, having a formal collection process in place more than pays for itself. Not only do you get paid a percentage of what you sent over, you get reports which help with future credit decisions. Keeping the sales staff involved at these times is critical because many times the salesman can get the customer to pay to avoid the lien or collection effort.
And last but not least, you need a rental-friendly system to help your employees navigate through this process with valid, current information. If you don't have such a system in place, you will be spending a lot of time pushing paper around as your AR balance grows.
The rental business is made up of two steps: rent it and collect it. I hope you are concentrating on both.