You never have to file.

And if you don't the IRS may assign a tax bill to your company via random number generation or whatever crazy valuation they're using at the time for your type of business.

Best for very person (SS number) + every entity (EIN) should file a tax return, even if $0 tax is required.

If the IRS assigns a tax value, you will spend countless hours trying to straighten this out.

Also, if you have an entity which is fallow (no longer used), shut it down, so you can avoid undo paper work filings every year.