We had help from both sets of parents with our house deposit and through university etc.
PILs pay for an extended family holiday every couple of years and always pay if we go out to eat or anything (we always offer, but they only very rarely accept). Their attitude stems partly from the fact that DSIL's family is on a tighter budget than ours (in a middle-class, no holidays kind of way, rather than a worrying about feeding the kids kind of way) and they want to treat her and DH equally.
My parents will treat us to an occasional meal etc, but generally we pay for ourselves. My dad has given us huge amounts of practical help (e.g. designing and fitting kitchens and bathrooms), which has obviously saved us a lot of money.
Both sets would help us if we asked and could afford to do so. I know that makes us very lucky. We are basically financially secure because of our family backgrounds and that is a huge privilege.
On a more general note, I never understand why trying to avoid inheritance tax (e.g. by giving allowances etc) is seen as so totally socially acceptable, even by people who would not, say, pay a tradesman cash in hand, or the very many of us who moan about corporate tax avoidance. It basically is tax avoidance, and tax is there to support society. It's an obvious way of redistributing things a bit so the glaring inequalities between people are reduced. Isn't it?