Here's my universal advice - MINIMIZE what you carry into the parks each day as much as you can. Judge carefully among suggested items here as to which your family will want/need. Lots of folks carry tons of extra stuff with them at WDW, and it's a mistake, IMO.
Avoid backpacks like the plague if you can. At the entrance to each park, you'll have to go through a bag search.
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Ugh!
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If you must have a bag, a see through bag is easiest. (you can find them at big box stores like
Walmart and Target. I just saw some at L.L. Bean) or at least somethign easy to open. If you are only bringing non-valuables, and you have a stroller you an put all in a clear (zip-lock) bag inthe stroller basket and skip the searches. In one sense, the searches don't slow you down al that much, but at peak times they are a real hassle. Avoiding them
will make life happier.
The less you have, the less you have to keep track of. This is especially true for kids. Remember, at each ride you have to stow your bag, and remember to pick it up when the ride is over. You are excited, you are inthe moment---it's SOOO easy to forget to grab that camera out of the pocket onthe ride- and who wants the stress of having to think about it each time- plus keeping track of the kids' bags....NO fun if you have to go back to find something. Trust me, been there, learned. Once my SIL made her kids carry bulky walkie talkies. They were useless, had poor reception, were a total pain to carry. Even though the kids were great, it was one more thing
I had to watch for...when SIL was able to join us, she ditched them after one day. How unhappy will you be if your child loses $20, $50, $100? Carry most (all) of their cash for them!!!!! Too many times I've heard parents yelling at their kids over lost cash in WDW. UGH!!!
If you don't have a stroller, that big bag will feel like lead at the end of the day, especially if you also have to carry a sleeping child (a very popular accessory at WDW) . If in doubt, bring a stroller, even for your seven year old. WDW is LOTS of walking. Improving the endurance level of the child will make the trip more enjoyable for everyone, though going stroller free can also be a treat.
I like for the males to wear cargo-type shorts. For myself, I also look for pants/shorts with lots of secure pockets (usually khakis/cargo shorts as well). Zippers are best, velcro so-so, buttons so-so. Good male cargo shorts can carry: camera, wallet, two water bottles. Knee pockets on my pants that are big enough to secure my cell phone are a huge plus. (If your cell phone is in a bag, you often won't hear it. Add 'vibrate' and stow in a pocket.)
Cell phones are great at WDW, esp if each adult has one. Makes regrouping SO much easier.
Personally, I like to speed through restroom stops, so I look for clothing items that are easy to deal with in the restroom - I avoid belts and ties, for example. I'd amplify that with kids' wardrobes, too: infant t-shirts over onesies that require snapping.
I'll say moleskin can be a trip saver. Moleskin kind of works like a band aid, but better. I once got a gash on my ankle before a WDW trip, and moleskin saved my ability to walk. A tiny bit in the wallet will work for park usage. with a package in the room, cut into strips.) Remember also that some medical supplies can be had in the parks. Maybe not at the lowest prices, but a dollar for a few Advil is no biggie, IMO. Don't skip an epi-pen or asthma inhaler or anything of the like. A few tiny Benadryl tablets don't take up much space, and can literally be a lifesaver.
In general, Rick Steves says to pack for the best case, not the worst. He's right. Especially when it comes to what you have inthe parks. It is not a bad idea to have a few extras in your suitcase in the room...just don't carry them all day. In most cases, you can survive without an item until you get back to your room. Though I hate doing laundry on a trip - one round only, if I have a long trip.
We do check weather each morning. Then we know about bringing jackets or rain gear. If you can skip dealing witha jacket all day, so much the better. In cold months though, a trip back to your resort room for long pants at night may be a must.
Avoid wearing white t-shirts (or any see-through- when-wet clothing items) if you plan on riding any wet rides: Kali at AK, Splash at MK, several rides at US's IoA. For Kali, I also like wear shoes that can get wet that day.
Don't wear sneakers or denim on Kali!!!!!
That brings me to my shoes tip. Bring at least two pairs of comfy walking shoes: sneakers and sandals. No matter how comfy, being able to trade shoes is a trip saver. Don't bother bringing any shoes that aren't comfortable for long distances, no matter how cute. The same goes for clothes. You will wear nice khaki slacks to TS dinners, but probablynot beyind that. For nice TS dinners, bring something nicer than character t-shirts, but not something that can't also be worn into a park. Cheap flip flops are compact and can be handy for the pool (not good for parks), but
Crocs or slip-on sandals can do double duty. Too often I see folks waering flip flops inthe parks - it's too easy to stub your toe, and then you may have a hard time walking. Long term they are really bad. It is VERY worthwhile to invest in high end sandals and quality sneakers with good support for WDW. Eccos are my new favorites, Clarks sandals are good too. Crocs are okay for a budget answer, if you can stand the way they look. If you have any foot issues, try a runner's store if you have one locally.
one item I will make some exceptions for is water. Drikning plenty or water is essential to great trip. It will help keep you from getting sick, and keep you from getting dizzy in the heat. Ask for it at every meal, carry a water bottle (refill if needed), keep kids hydrated. When choosing beverages, drinking juice or lemonade over Coke can also help. Lemonade also has vitamin C.
I think kids who flash flashlights on ride annoy everyone else. If you have akid that is sensative to noise though, swimmer's earplugs may be worthwhile. They can also help on the plane ride.
A TINY bottle of hand sanitizer can come in handy. Staples has them. In apinch you can get by without this item though.
There are lots of penny machines at WDW. I don't normally use much cash at home, but having change at WDW makes for inexpensive souvies. Eventually those quarters add up, but a few pressed pennies are great little things. If you use some cash, you'll find it easy to have quarters and shiny pennies, but if these are a real hit with your family, then a tube of quarters/shiny pennies is a good thing. an empty mini-M & M's tube is just the right size for them. You'll need lots of quarters for laundry too, but usually there's a quarter machine in WDW's resort laundry rooms.
I woudn't carry them all day, but for evening, glowsticks are a treat in the parks. Glow necklaces for $1 are far less $$ than the things they sell at WDW, but the ones they sell are pretty cool, esp in MK, if you'll be there at night.
Your kids might be too little, but glitter hairspray - AKA - pixie dust- can be fun for girls. A lot less $$ than BBB. (Or any glitter body spray)
Another inexpensive treat that cn be found at party favor stores are Disney temporary tatoos. Much less $$ than the ones they sell at WDW, though getting one at WDW can also be a relatively inexpensive treat.