Unless these are all small balances, I would think this risks considerable loss of revenue that otherwise may be collected. If charges were billed to the correct payer within the timely filing period and there is a denial, these may still be corrected and refiled or appealed (see your payers timeline for appeals as this may be anywhere from 60-180 days). There is an obligation to make a good faith effort to attempt to collect outstanding balances, especially patient balances due after the primary has paid. While the time of staff to follow-up on claims can be expensive, if balances are more than minimal, there should be a return on the investment. I used to work as a temp going into practices and working old A/R and usually a good deal of it was collected.
If your providers choose to write-off everything over 120 days, it is advisable to look at the accounts and make sure there is indication of an effort to collect on the charges and when known, a reason for the write-off should be entered (e.g., past timely filing, patient moved with no forwarding address).
I hope that helps.
Cindy