Listen to Don! Except I think he meant to say illegal to tint the windshield, unless he meant he only did the top. I think 3 don't allow at all (NJ, PA, MN). I see people with the whole thing done in Texas, but I think it is only legal with "medical justification".
I am in Houston, where our sun is not as bad as LV, but our humidity is typically much worse, and the sun is still pretty brutal in the summer (triple digit heat with 95% humidity is normal from anywhere between 10-30+ days a year). So heat is a pretty big concern.
My tint is 18% all around except windshield. Most states set their rules by NET tint, so keep that in mind when selecting, at least if you care!
We are only allowed 35% tint on the front windows (30% NET visible light is the rule, but auto glass blocks ~5% - so the aggregate of the 35% tint + the 5% glass is 30% visible light pass-through), we are allowed anything you want on the back windows (but be careful, I will explain at the end), and we are allowed windshield tint in Texas, for the top 5 inches, or to the AS1 line if you have it, and is just for you eyes, not for heat protection. Personally I don't like the way this 5 inches of tint looks, unless it is really light, and then what is the point of doing it?
Most inspection shops in Houston will let you slide with front windows, just roll all windows down when you pull in, and leave them down as you pull out, but the windshield is so obvious most inspection shops will not let you pull out with a sticker, unless you "grease the inspector".
So to the part about being careful. I had a Ford Explorer in the past that had Limo tint all around (8% visibility + 5% glass). When the thing was spotless, during the day it looked amazing, I had nothing else done to the truck at all, bone stock, and I got a lot of compliments, and a lot of questions as to where I got it done.
However, visibility was a major problem!
I would not allow anyone to ever drive it at night, because unless you had spent a lot of time in the car, you could not see other cars beside you at night, even when they had their lights on, and the biggest PITA is that, I had to roll down both front windows every time I had to back up at night, often sticking my head out of the window (really fun on rainy nights!) because the reverse lamps and the did not provide enough light for my rear window to be of any use. I could see headlights behind me, but my passengers always complained they could not see anything. It took serious adjustment, and even after driving it like that for a couple years, I still couldn't backup at night.