Kind of off-topic thought
There was one Amazon review that blamed a Miele customer agent for recomending an empty boilwash once every month or so.
Customer was in rage.
Looking at it, an empty boilwash in an empty Miele uses less then 35l of water and less then 1kW of energy.
So, over here, a machine cleaning cycle impacts efficency equal to one fully loaded warm wash, give or take.
So basicly, equivalent to me having a friend stay over one night or not.
Or me spilling salsa on my favorit TV blanket.
Like, seriously, every 40 cycles is a bit often in my opinion, but if you do it once every 100 cycles, that cleaning cycle makes up about 1% of the washers energy and water usage, approximated.
If - for a normal warm wash - a FL uses half of everything a washer without cleaning cycle uses (and that is conservative), a clean cycle on a FL would have to use the equivalent of 20 or 50 normal warm FL washes respectively to get the FL and TL equal in operating cost.
So, even if done every 40 cycles, the usage won't cancel out the savings.
And for those who say there should be no need to have such a cleaning cycle: I don't think you should have to clean a dryers cabinet every other year. But, as far as I understand, that is considered normal dryer maintanance.