‘Fred and George have invented Extendable Ears, see,’ said Ron. ‘They're really useful.’
‘Ears, yeah. Only we've had to stop using them lately because Mum found out and went berserk. Fred and George had to hide them all to stop Mum binning them. But we got a good bit of use out of them before Mum realised what was going on.
Harry Potter and the Order of the Phoenix
In my opinion, "got a good bit of use out of them" probably means make good use of them or benefit from them. But I'm not sure what it means exactly here. Any thoughts?