Daily practice question

It deppends on which part of your voice you think you need improvement. For me volumes 2/3 are nice for an overall workout of chest, bridging, vowel mods, stamina, etc. However if support seems shaky, then spend some time on level 1. If you wanna sing a song that demands more headvoice/mix, then lean your focus on volumes 4/5 more than the others.

The voice can always be improved. You should watch yours, record yourself, and decide where to go from there. With time you'll notice which exercises work best for you, etc. Hope it helps!

I think it depends on how your voice is at that day. If chest is weak you'd focus on bringing it back. This while never neglecting the warmup exercises, tongue and simple triads to slowly wake up the voice. Ken's always mention the exercises should have a practical song application, so depending on the repertoire you'll sing you can pick the exercises to a particular goal. Always start small and slowly go warming up.

Ken mentions he would wamup for 1 or 1:30 hours for a show, while also organizing the repertoire so it's not too heavy on the start, etc. You can find some warmup/performance videos on his channel. Didn't watch this but might have some good info: https://www.youtube.com/watch?v=bwKZNZh_mPs