One of the things I do at the start of fall is to make a sort of "bucket list" of the things that are important to me to do to celebrate the holidays. Then I plan to make those things happen.
For example, one of the things I love to do every autumn is visit a local apple orchard/winery and have lunch there (they have a little bakery and deli where you can get fresh cider, pumpkin-apple doughnuts, etc.). I make sure to plan time to go and do that. This year, I'm also planning to go on a scenic drive to enjoy the fall colors. Since I work full time during the week, I have to decide which things I can do on the weekends. When I know what I want to make time for in advance, then I don't get distracted by things that I could do at any other time.
In terms of throwing parties, unless your family or circle of friends has a regular habit of getting together impulsively and is used to last-minute invitations, I find that it works best to plan in advance due to how jam-packed the holidays usually are with all sorts of events (and therefore, schedule conflicts!). At the holidays, everyone in my family has such different schedules. We are all married and have to balance events for both sides of our families. We usually decide on dates for the family Christmas party, etc., months in advance because it is important to us that everyone can be there. When events are announced at the last minute, sometimes, someone can't come because they've already committed to something else.
In short, I think you have to decide what matters to you and what really "makes" your holiday season. If doing certain things and seeing certain people is really important, then advance planning increases the chance of making those things happen.
