go on for an age
To persist or continue for a long time. If you ask Grandpa about the weather, get ready for him to go on for an age about the Farmer's Almanac. It feels like this baseball game has been going on for an age.
go on for an age
and go on for agesFig. to continue for a very long time. The symphony seemed to go on for an age. It seemed to go on for ages.