On our first WDW vacation 17 years ago, we carried around a lot! I had a regular, full sized purse with wallet, sunglasses, phone, camera, touch-up makeup stuff, chapstick, pain meds, wet wipes, WDW travel guide, etc. On top of that my husband lugged around a large backpack holding 2 large water bottles, camera, tripod, his wallet, sunglasses, ponchos, and my extra stuff that wouldn't fit in my purse! lol Did this for about the first 3 trips, and then we lightened up a bit.
Realized we didn't need all those pills: buy from the stores within the parks as needed, or go to the first aid station.
I wasn't touching up my makeup as much as I thought I would: So busy touring the parks, and after awhile I started caring less and less how I looked to other people!
Ponchos: Will eat the cost and buy at the parks if needed. These can take up a lot of space in a backpack.
On our most recent trip I downgraded to a small crossbody bag and just carried my wallet, chapstick, blotting tissues, eye drop vials, sunglasses, and phone. My husband still carried a smaller backpack which contained his wallet, phone, sunscreen and sunglasses, and just 1 water bottle that we share.
Money tips: always, always carry around multiple methods of payment! On 2 trips we had money issues; Rainforest Cafe's credit card system was down, and were only taking cash. We asked about an ATM, but either there wasn't one close by, or it was down too. Can't remember, but we did inquire. Those of us paying with cards had to wait 45 mins for the system to come back online! The other Disney trip we got stuck at Emeril's restaurant after both our debit cards were declined. Hubby had to take cab back to Disney CBR, (while I waited at the restaurant), to grab a different credit card, which we kept in the room safe. Ugh! Never again. Always carry cash, or at least one extra credit card with you.
Since our money issues, Disney came out with magic bands, so that helps on property. Nonetheless, we still carry 2 different credit cards, and a bit of cash. You never know!