"Evergreen" trust accounting is now available in Time59.
This feature allows you to specify a required trust balance and also a trust balance threshold amount that, when reached, will trigger a request to the client for replenishiment of the trust account to the required balance.
Here's an example...
If a client has a Required Trust Amount set at $1000 and a Replenish Trigger Amount set at $500 and a trust balance of $406 then a line item will appear on the client's invoice requesting $594 to bring the trust balance back to $1000.
This will be completely automatic and you can adjust the Required Trust Amount and Replenish Trigger Amount at any time.