8 mistakes tourists make in Disney World, from a former employee who visits 4 times a month

Although some Disney items are always on the shelves, others sell out fast.

I've witnessed people leave an item for later only to find the merchandise sold out across the theme parks by the time they returned.

If you don't want to carry bags of souvenirs around all day, many shops offer to ship your purchases to a home address.

All quick-service food locations and stands with soft-drink fountains give out free cups of water. Avoid the food carts and smaller stands because they don't have fountains.

You can also opt to pack a refillable bottle — I suggest a metal one to keep the water cold — because there are various water fountains around the parks.

It's hot at Disney World for most of the year, and nothing's worse than carrying additional weight when trying to stay cool.

You can rent a locker near the park entrances if you need to bring more than what fits in a small, comfortable bag. They start at $10 a day and your items will still be close by.

Pro tip: Be sure to pack hair ties if you have long hair. It's almost impossible to buy them in the parks.

I've seen people make a list of activities to try at Disney World but get sidetracked and run out of time before completing it.

Do whatever research works best for you — you can read the park's website or watch videos from past visitors — and list things you want to prioritize for a successful trip.

I've noticed that when guests don't get their desired dining reservation, they often settle for another restaurant.

Reservation availability at Disney World changes frequently, so be persistent with checking the My Disney Experience app. Most of the time, what you're looking for will eventually become available.

There are also third-party sites, like MouseWatcher, that can alert you when reservations become available.

I've often seen families surprised when they're forced to clear out of Magic Kingdom early because Disney's about to kick off a special event, like Mickey's Not-So-Scary Halloween Party, that they don't have tickets to.

In some cases, if you're at the parks on an event day without an event ticket, you could even miss Disney's fireworks show.

Even if you don't plan on attending a ticketed event, keep an eye on them and how they factor into your trip. This will allow you to maximize the hours spent in each park to maximize the value of each ticket.

Although Disney World is a ton of fun, it's tiring. I consistently see people underestimate how much energy it takes to run around the parks.

Be sure to plan for some downtime so your visit doesn't feel like a chore. Some options include relaxing at a pool or sitting and enjoying a live show.

Some tourists seem to wear clothes and shoes that are comfortable for only a short period of time, not for a full day of walking.

Light, breathable fabrics are best. For shoes, I always suggest Crocs or other comfortable, waterproof shoes in case of rain or a water ride.

It's nice to take cute photos in fun outfits, but staying comfortable makes the day so much better. Pack an additional outfit in your bag if you need to, but be sure to prioritize staying comfortable and cool in the parks.