Scheduled maintenance/outage in my area, how long does it normally take?

Unable to connect with an agent over the phone (very inconvenient) just to ask a simple question without automated system trying to troubleshoot my equipment. 
My internet is working fine right now but I received text yesterday that x finite is doing maintenance that *could* start as early as 6 am (it’s 7:23 am as I write this) how long does the outage normally last for? Just knowing how long it is at least would be nice, as well as more accurate start time