Last time I was in Las Vegas was 25 years ago. I wonder if anything has changed? *\;-) (I wouldn't know it if it had, though.)
Trust me: You WILL notice the changes, especially if you fly in at night. There are so many more casinos and theme parks than there were when you were here, last. The streets are much wider and MUCH busier, and depending on where you stay, people are ruder.
You’ll have fun, though, because there are lots of things to see for free, depending on the amount of free time you have.