I just use them for out of cage time. With a very old doddery hamster I sometimes put a fleece item in the cage as they are past chewing things usually by then
I think he has been a bit freaked by Moo dying actually. Moo's cage was underneath his and I think Pickle must have been very much aware when Moo passed. Plus he is no longer there of course. They had been in a sort of sync sometimes and when Moo stopped coming out of his house, Pickle did too.