OK - some background...
When my son was a baby he occasionally got nappy rash. When he did we used Sudocrem and it sorted it. Once he was clear we stopped using the cream.
When my daughter was a baby she had fairly bad ezcema and we used a lot of different creams on the various parts of her body that needed them. Her bottom was one of her flare-up points and so we were regularly using a combination of metanium (sudocrem never worked for her), daktacort and a few different hydracortisone creams. Her ezcema is much better now and she very rarely has flare-ups which can be treated with simple aqueous cream. She was potty trained a year ago, although is still in pull-ups at night. She is almost dry at night and always clean.
So yesterday her bottom suddenly flared up - bleeding etc... and as I had nothing in the house bar oilatum I called the doctor. She was prescribed a hydracortisone cream but I was told I should still be using a barrier cream at night anyway. I explained that her skin is generally fine (it's been over a year since she has had a flare-up like this) but the doc's response was that barrier cream should be used with EVERY nappy change from birth through until the child is completely out of nappies day and night regardless of skin complaints! I was really shocked! Do people actually do that? We've only ever used creams when needed and that's with a child with ezcema! The doc made me feel like the worst parent in the world!