Should guys refer to the opposite gender as girls, ladies, or women?

Girls from 0-29, women from 30-49, ladies after that.

I've been called all three. It makes no difference to me.

If you're looking for the terms least likely to offend anyone: "girls" under 18 (or pre college), "women" otherwise..."woman" means a female human old enough to procreate and American culture pretends that happens at age 18. Some people who care about such things will view "ladies" as roughly synonymous with "female humans who refuse to engage in serious pursuits".

Going this way won't tend to offend people who don't care about such things. Exception: you're probably best off referring to anyone you suspect is socially conservative as "ladies". Many social conservatives are offended by political correctness.

This is what I think:

Girls for under 30.
Women for anyone else.
Ladies only for those women that behave like a lady. I feel to be called a lady you have to act like a lady. I don't feel the women that are immture that treat people poorly deserve to be called ladies.

If you want to be polite, then "girls" if they're children or teenagers; "ladies" or "women" if they're adults.

However, it doesn't really matters, and it all depends on your personality. For example, I've been called, Pretty/beautiful lady/woman, sweet/pretty girl (by men 60+), ma'am (by children/teens), Miss, etc. As long as it's not "Yo bitch," or something insulting, women don't care.

Depends on the girl you are referring to... there are girls, their are ladies and there are women. All "females" can be all of the above depending on their behaviour but for arguments sake, I'd stick with calling children girls and adults lady. Far less women will be offended being called a lady then a lady called a woman. Complicated much

My wife gets called a slut so somehow she doesn't fit into the criteria.

Whores works for me if they are 15 or older.

I prefer "ladies" when speaking to preschoolers.