We had a nest box which had a hole just large enough for blue tits who used it for several years but one year we noticed a great tit pecking around the edge of the hole to make it larger and she used it that year. A couple of years ago we had a family of robins in our robin box - but not since, also coal tits nesting in a hole in a wall for several years but no longer.
Obviously there are better mansions around here now.
Good Morning Tuesday 23rd April St Georges Day