Leather
It breaths, allowing some moisture out. Hard work and sweat will see any boot get moist by the end of the day. Synthetics take a long time to dry out. Leather flexes and will take on a shape according to the wear and use involved. Synthetics retain their shape and end up causing blisters. Break in the leather boots by wearing them for a couple hours per day while doing some light work, walking around.
Not all leather boots are created equally. Different cuts from the hide, different tanning methods, different stitching. Those cheap leather boots you can get at the big box store for 30 bucks won't hold up. Better brand names include Justin, Wolverine, Timberland. Do you go for a $30 boot that lasts maybe 6 months or a $200 boot that lasts a couple years? I've done it both ways. Those durable, high quality boots are expensive, but your feet will thank you. If conditions are kinda nasty and would ruin boots in short order, go with the disposables for those jobs.
Steel Toe
Physical work will have the wearer kicking and dropping things. It does not take much to break a toe and a broken toe is not worth seeing a doctor, getting a cast...get the steel toes ad save a whole lot of grief.
Steel Shank
This is a steel bar in the sole of the boot. It protects the bottom of the foot when stomping and walking on rough surfaces. Makes life easy when stomping a shovel into hard ground.
Waterproof
Wet feet in boots can be tolerated for a few hours. Wet feet in boots for many hours will cause distress and can take the worker off the
job. A splash here and there is expected and you'll get wet feet from time to time. For that occasional splash, swap your wet socks for new socks. Keeping your feet dry for long work days demands the boots don't allow
water to seep in. I've seen guys treat their boots. In an emergency, WD-40, motor oil, even bearing grease will offer protection, but some of these solutions will wreck the boots. Your boots
should be waterproofed as part of the manufacturing process. As they get scuffed and scraped, they lose that waterproofing. Google this: Nikwax
Lace Ups vs Pullups
Pullups are easy on, easy off. After a while they can lose their snugness.
Lace ups can be tightened as needed but the laces can get caught on machinery, sticks, obstacles.
My preference is and shall always be pullups. I'm just too danm clumsy, and that's on a good day.
Height
I hear Arizona is kind warm. no matter. Get the high top boots. They'll be warm but they reach above the ankle. There are low top boots out there, but if you are even a fraction as clumsy and awkward as me you'll save not one but many sprained ankles. If this is your daughter's first time in boots, she'll be awkward. Get the high tops.
Now let's talk about socks.
Heavy Duty or Industrial Strength durable socks, reinforced heel and toe. I get more holes in the toes than in the heel-moving my toes for leverage wears them through. When the heel wears out, they are finished. I like those with arch support. Some cotton in the blend makes them cozy. You'll spend 10 bucks on a decent pair of socks. Be sure to try on the boot while wearing the socks. These socks are bigger than normal crew socks and can make a pair of boots a little too snug. You might want 1/2 size larger to account for the socks. I can stand old ad beat up boots if I have my awesome socks. I tell you, I freakin LOVE my socks. I don't care about the boots. Awesome socks will make crappy boots bearable.
The socks need to be as high as the boot at least. Too short and the cuff of the boot will rub your leg.
Get extra socks so you can swap them if your feet get wet.