You can file a lawsuit at any point, but, generally, it is optimal to wait until you have completed the appeal process before filing a lawsuit. There is a chance your denial will be overturned, making a lawsuit meaningless.
Additionally, your Reno long-term disability lawyers can use the actions of your insurance company during your appeal to strengthen your case if a lawsuit is necessary.
If you want to file an early lawsuit because you need money, Leverty & Associates Law Chartered lawyers can direct you to resources to help you stay financially stable while waiting for an appeal to complete.