HB wrote: advantages of on/off cycling:

• Saves energy

This, and the question of safety in having an electrical appliance left on all day, are arguments that I'm not sure hold water (please excuse the unintended horrible pun. OK, so it was intentional!) I'm not sure that heating the thing up two (or three) times a day requires less energy than maintaining that level of heat. It could, and I don't know, but it feels like leaving it on is just as efficient if not more so.
As far as leaving an appliance on all day, it's pretty much a water heater. Anyone turn off their water heater when they leave the house after the morning shower? You folks in Europe that have the hot water on demand shower are excused from this quiz...

Technically speaking having crunched some numbers I'd say cycling on and off for example 3 times a day with total on time 6 hours per day would save energy and hence $, but not much. Depending on machine and local cost of go juice likely save maybe $20 per year versus $30-$35 annual cost on 24/7. Given such a huge annual savings estimate I've elected to keep my Bricoletta on 24/7 unless leaving town.

I had my Isomac Tea on 24/7 for two years. I would shut it down if I left for a weekend, but that's it. I finally came home to find that the p'stat had stuck "on" & overboiled the machine (melted the reservoir, pressure gauge lenses, flooded the kitchen.)

I ended up just upgrading to a machine that I know will safely run 24/7. Whenever I repair the Isomac I certainly won't run it 24/7.

I do sometimes cut the power to the Cyncra's boiler elements on hot days, though, as I don't have A/C. It gets back to temp within 45 minutes from idle.

I have pondered this question for some time. My conclusion to the leave it on or turn it off question, there is no answer, whatever works for you is the correct response.

I have insulated the boilers on both of my machines which appears to substantially reduce the boiler cycling and hence energy consumption. My Isomac, which resides at work, I turn on in the morning when I get to my office and turn off when I shut down my computer. A 1.5 liter e61 heats quick so time is not that big of an issue, provided you plan ahead. On hot days, I will cycle it on, pull a shot an hour later and turn it off until next time.

The Faema is a different story. A commercial machine takes about two hours to come to temperature. During the summer, I still power it down when I leave for work. It just pumps too much heat into the house. I have the wife turn it on about an hour before I leave so it is hot and ready when I get home, then off again for the night. During late fall winter and early spring, I will leave it on since heat is not a problem.

Group gaskets are cheap and easy to replace. You need to pop that dispersion screen off now and then to clean it anyway. The internal components are designed to take the heat. There may be an O ring that hardens over time and needs replaced but consider you are talking about a $.19 part and only a few moments to replace. Once again, a perfect time to clean the inner workings of that steam valve or water tap, nothing keeps a machine in top working form better than some occasional preventative maintenance.