> Monastics live in windowless rooms

I have visited dozens of european monasteries – I can't remember ever seeing a windowless cell or a dormitorium. Even anchorites’ cells have windows.

Which makes sense given the medieval times: available light sources are candles and outside light. But also monastic life was focused on the Liturgy of the Hours which as the name says takes place on determined hours – and since it was late antiquity/early middle ages these were temporal, seasonal hours, depended on daylight. If you read the Rule of St Benedict you'll find diverse chapters which try to fit the monastic schedule into the available daylight and arrange the schedule to the seasons.