Length of audio lessons

What length do others find most ideal for the audio lessons?

I've always found 30 minutes to be too long and now with everyone home thanks to travel restrictions I feel like I'm lucky if five minutes goes by uninterrupted. I wish the audio lessons were either shorter or had finer controls and better bookmarking.

Does anyone else feel like this? 

Taking normal times into account, it can sometimes feel laborious, but when I reflect on them, the content has always been relevant.  I’d rather have it drummed into me and remember it, as opposed to having it skimmed over. In a nutshell, the system works well for me.