In all fairness to Russ, I reflect upon two things.
1. Russ
has almost entered the 30-something period, and presumably dates women near his age, maybe older, and quite possibly slightly younger. While trying not to generalize, there does seem to be generational (and perhaps geographical) differences. The sensitivities of women in 30's, 40's, 50's and older, seem to be different than those of women in teens and 20's. I have seen it and women of different ages have made this observation. However, that does not give license to men of any age to use terms of endearment inappropriately, and by that I mean, men should not be familiar with those women with whom they are not.
2. The use of terms such as "babe" or "baby", has been ubiquitous in popular culture, and we are all aware how popular culture influences behavior. For example, 2nd song on Led Zepplin's first ablum, "Babe, I'm Gonna Leave You", and I distinctly remember a Jimi Hendrix song in which he sings "Hey babe." Again, this does not give license to men to use terms of endearment inappropriately.
The point at hand is "how to determine what is appropriate".
Simple - a man can simply ask a woman with whom he has contact!
BTW - If I used 'baby' in addressing my wife, she'd punch my lights out!
Actually she has told me not to use it in the past. The exception is 'poor baby' when she is ill or feeling poorly. Even then I rarely use that expression, even though she has said it is OK to do so in that circumstance.
I usually limit my use to 'Sweetheart'.
Oh, and I never make assumptions about what my wife is thinking - even after knowing her 25 years!