"Mobile never turned on. Phones are for DF to ring people not for people to ring him."
My dear brother used to keep his mobile off, even when driving 200 miles to visit Mum, who would want to ring at some point in his journey to get some idea of when she would best start cooking, so he could eat soon after arrival.
My BiL (admittedly until recently on parish council) also kept his mobile off more than on. Perhaps now my sister has retired they might both keep them on (however, logic dictates that as they may be out together, odds are they 'will not need them' so phones might be off, or in car, or at home, anyway!)
My eldest sister (new to a contract mobile with hundreds of minutes) now seems to ring at any time after 20:00. The most recent call started at 22:15 and went on to 00:30 (I was in bed snuggled up by then!). Ring her and 99 of 100 times it goes to voicemail, with no guesses at how many hours or days before she may ring back.
She has rung up before now at 23:30 ... and to be fair, one of my clients rang around the same time on a Saturday night a couple of years ago, desperate for me to remove a virus that was preventing him from printing flight documents needed for a flight on the Sunday after lunch!!