I am so lucky - I have two lovely, thoughtful DILs. I don't think we could have better if DH and I had chosen them ourselves. I do a lot for them, especially the one with children, but they never take anything for granted and it's definitely a two-way thing, with them, not our sons, being the ones to arrange little treats for our birthdays etc. or sometimes for no special reason at all.
I hope I don't sound smug. I certainly don't intend to, as things felt very different when DS1 was with his first wife. I can well imagine that if that relationship had continued, I could now be a regular poster on the 'cut out of their lives' threads. I often read those posts thinking 'there but for the grace of God ...'.