In humid conditions (>60%) I've run it 24h without problems at 50%. Under these conditions the tank takes about 2 days to fill. That being said, the power consumption will be relatively high. As a compromise, I now set the timer to 1-2h and let the humidity stabilise before it shuts off. Also, running it in "turbo" mode may shorten the compressor cycles which, on average, can reduce the consumption a bit. This thing is really loud in this mode, so this is only practicable if operated in another room.

In humid conditions (>60%) I've run it 24h without problems at 50%. Under these conditions the tank takes about 2 days to fill. That being said, the power consumption will be high. As a compromise, I now set the timer to 1-2h and let the humidity stabilise before it shuts off.