I'm the gift-buyer in our family, not for any particular reason but I've sort of slid into that role. DH is one of 5 siblings, 3 of the others are married and there are 4 nephews and nieces on his side if the family (and counting). Last year I bought for everyone except FIL and BIL and asked DH to sort out presents for them. They got socks and a hat, hastily grabbed from Asda on Christmas Eve 
This year I told him I was leaving birthday presents and cards to him. I reminded him frequently when birthdays were coming up and sorted out presents and cards for the DNs. FIL got a card. MIL got a card. BIL2 got nothing. SIL1 got a Facebook message. SIL2 got nothing. SIL3 was promised some money. BIL1 got nothing.
I'm doing Christmas...
What would happen in your house if you're the main gift buyer but you left it to your OH to do the presents?