So now you know you need sun screen.
Reality, I keep a Trip bag at all times and add to it anytime I see good deals for WDW or travel in general. I get more specific as dates of planned trips approach.
As the Summer comes to a close look for sales on:
Sunscreen...but check to dates on it.
Summer travel toys....Cracker Barrel has a huge selection and are good about marking down.
Replacements for summer clothes... Feb is still iffy weather in Florida... you may need summer or winter or anything in between but you will for sure want to at least pack a swim suit.
I also keep my eyes out for sample size products, especially Disney themed
Disney themed items such as band-aids, snacks (as date gets closer but remember many food's dates are MONTHS out), t-shirts, socks, etc.
Watch for sales on bags, cameras etc if you need these items.
Plan your new tennis shoe purchases so shoes are well broken in but not worn out. Maybe new shoes for Christmas for everyone.
I also pick up things like ponchos, disposable tooth brushes etc a few things at a time, anytime I am in the $ store. Free samples are also a great way to add to your needs list.
We travel a lot so we just pull from the huge bag as we need to and restock constantly.