OK - item 1 - DON'T slice into the side of your finger with a breadknife (no alcohol involved!) meaning that, along with many other daily activities, typing becomes difficult!
Otherwise:
Yes to buying ahead and keeping the spreadsheet updated throughout the year.
Although, there is 1 problem with a whole extended family announce a week before Christmas that they got a shared hamper to the smaller extended family (hah! Bad idea as DM took it all except the port which we insisted on opening Christmas night, knowing we'd get nothing else!) and I'd bought for them all.
Reduce the budget for everyone!
We spent loads on everyone and got not a lot back - I know you don't give to receive but...(DH got a €5 dancing santa from Tiger while he gave his DB a €70 print, I got a €5 peppermint candle in a jar (not Yankee) while DSIL got a hamper of sanctuary stuff from us costing almost €50! - DH was quite upset by that one, I know better than to expect much).
Secret Santa worked reasonably well in my family again, but I spent too much on stocking fillers for the non-Santa people (we buy 1 big gift each, we do a draw for the recipient in advance, and then €5 or less, or homemade or regifted stocking fillers for everyone else).
We want either to stay at home ourselves next year, or go away skiing or to Australia/New Zealand. We've done family 2 years in a row and it's very hard work and expensive for us - and there is a complete expectation that we don't need a holiday but that just being there is our holiday (poor DH sat down on 27th for 10 minutes to watch a movie - the first all week - and his DM sent him to take his DUncle for a drive as DBIL was "too busy" - DH had spent all day up to then doing chores for his DM!!!).
We've learned that a nice set of Leonidas chocs works really well for us instead of tubs of Roses/Quality Street etc - we spend the same but have far fewer calories and actually enjoy the choc!
Sarah Raven's mince pie pastry, with Hairy Bikers' mincemeat inside (it had matured for 18 months) works really well! I am going to try and get a fresh batch of mincemeat going this week for next Christmas consumption.
Keeping the cleaners on their normal schedule is good - we had a clean house leaving (sooo nice to come back to) and again just before the few days we'll actually spend at home - we've been in and out a bit between trips but actually get some family time at home this weekend.