I have found a week off after a 24-week was enough rest for me. For my first training cycle, I averaged just under 9 hours/week and for my second cycle, it was close to 11 hours/week. My previous training volume (prior to starting UA training) was maybe 3-4 hours/week. Due to COVID, couldn’t travel much. But I might consider a longer break between two cycles if I am travelling with family.
Also, I am not training for any race or event but for a climbing season and typically these are one-two day alpine climbs at less than 4000 m altitude. For people who train for high-altitude expeditions/big projects, I am guessing the recovery period/break after the climb would be much higher.