I don't think there's any one right answer to this question. It depends on how hard the component is on tubes, how long the component takes to "gel" from a cold start, time between listening sessions, how unpalatable (or conversely, inconsequential) re-tubing is to the owner, etc.
For example, my tube preamp (with internal phono stage) sounds great after a couple hours of warm-up. My tubed DAC, on the other hand, doesn't start to sing until it's been on at least 24 hours. As I'm primarily a weekend listener, I power things up on Friday morning before I go to work, ready for listening Saturday morning, and then turn things off Sunday evening. The DAC doesn't sound terrible after it's been on for an hour or so, but doesn't get the goosebumps going at that point. Neither piece is hard on tubes (a long time ago I had an Audible Illusions preamp that ate tubes for breakfast), and if either of these components were tube eaters my approach would change as I'm using some pricey NOS tubes. Finding out how long the tubes last in your pieces will take....well, will take until you need to buy new ones. :)
From a safety/power consumption standpoint there's nothing to worry about with a preamp or phono stage if left on 24/7. If I could listen every day as you do, I'd just leave mine on.
For example, my tube preamp (with internal phono stage) sounds great after a couple hours of warm-up. My tubed DAC, on the other hand, doesn't start to sing until it's been on at least 24 hours. As I'm primarily a weekend listener, I power things up on Friday morning before I go to work, ready for listening Saturday morning, and then turn things off Sunday evening. The DAC doesn't sound terrible after it's been on for an hour or so, but doesn't get the goosebumps going at that point. Neither piece is hard on tubes (a long time ago I had an Audible Illusions preamp that ate tubes for breakfast), and if either of these components were tube eaters my approach would change as I'm using some pricey NOS tubes. Finding out how long the tubes last in your pieces will take....well, will take until you need to buy new ones. :)
From a safety/power consumption standpoint there's nothing to worry about with a preamp or phono stage if left on 24/7. If I could listen every day as you do, I'd just leave mine on.