Only 9 days...

In only nine days I'll be off to Mexico for three weeks. So, the packing has begun.
In these days of expensive flights, and added fees for luggage, I'm trying to get it down to one checked bag and one carry on. Not an easy task for a three week trip.
I usually pack in the stages method.
Stage one was a few days ago. In stage one, I take out all the things I think I will need and all the clothes I want to take with. I put all of this in my suitcase and find out it doesn't all fit. So I bring our another suitcase and stuff it all in. Of course, this doesn't include things I still need to wear until leaving such as underwear, shoes, toiletries, etc.
Stage two was yesterday. In stage two, I take everything out of both suitcases and go through what I picked. I take out what doesn't work and ask the question, "do I really need this?"
Stage three will be in a few days. In stage three, I again look at everything, and take out some more. I may add in something I forgot the first time, but by now I should be down to one suitcase.
In stage four, a few days before leaving, I start to pack my carry on bag. Now, I can take a few things out of the main suitcase and put them in the carry on bag such as one swimsuit, underwear, and one change of clothes. Now, there's more room left in the main bag for shoes and other essentials that go in at the last minute.
When I'm packing to go to a place warmer than Wisconsin, it gets tricky. Because I have to have the clothes I wear to the airport and back home. I know that it can still snow in May around here so I at least need a light jacket, a pair of jeans and some closed shoes.
I've been checking weather.com to see what the temperatures will be like in Tulum. So far, 80s during the day and 60s at night. A friend said all you need is a swimsuit and a sarong. So far I have three swimsuits and four skirts, two dresses, and five sarongs, three pair of shoes, a sweater, five long sleeve shirts, a couple of t-shirts, light pajamas, a few scarves.....
I'll probably be wearing about five layers on the plane to keep my luggage from being too heavy.
I think that's why they call it a vacation, because all the stress is in the planning!