Totally worth the expense then.
The route was wired in 1981 - at that time there were some electric trains that ran Altrincham-Sale-Manchester-Hazel Grove, of course that's no longer possible now.
By my reckoning:
1981 to late 2008 - standard pattern of 1 electric train starting and terminating at Hazel Grove every hour
Late 2008 to mid 2018 - no regular electric trains to Hazel Grove due to an insufficient number of EMUs available at the December 2008 recast Northern decided to run diesel services from Hazel Grove to Preston, instead of an electric shuttle from Hazel Grove to Manchester.
Mid 2018 onwards - standard pattern of 2 electric trains starting and terminating at Hazel Grove every hour