During the night my 7-week-old will fuss in his sleep (grunt, flail, etc...). This fussing rarely proceeds to crying but he usually will not settle on his own. When I pick him up he will usually settle down and most of the time he is wet.
I typically treat this fussing the same as all out crying and respond to him immediately but it has been suggested to me that I may want to let him "fuss it out" for a while so learns to settle himself down (or at least until he starts crying).
I think that's good advice. Try to ignore light fussing. Wait and see if it develops into something more.
We were told the same by the midwife, and at least for us it was good. Most of the time, our son stopped fussing again on his own. If he didn't, we'd sometimes tuck him in a little and that would be enough. Sometimes it was the beginning of some real unhappiness (diaper etc.) which we of course responded to.
Knowing that it's okay to not act on many of the smaller disturbances allowed us more rest, which we appreciated a lot. We got plenty of nightly interruptions anyway.
I always responded to his whining and grunting, but now I wish I had not.
I now know that children need to learn to self-regulate or calm themselves independent of adult intervention. Learning this skill early is important for later emotional development and even supports problem solving.
My son struggled with self-regulation early on and I think I could have gotten him off to a better start if I had known what I did not know.
No, I would not treat them the same. If you give him a few minutes to try to re-settle himself, it gives him the opportunity to learn how to fall back asleep on his own. When he gets bigger you'll really appreciate him being able to re-settle himself and not waking you up between every sleep cycle. If he continues to fuss and does not resettle (say 5-10 minutes later), by all means go tend to him and help soothe him or feed him or whatever he needs to get back to sleep. My rule of thumb is to leisurely go to the kitchen and get yourself a glass of water, then go to the bathroom, then go check on him again, if he's still fussing, THEN assist him. If he's really hungry, usually the fussing will escalate into a "calling you" type of cry, which you may feel free to quickly attend to if you experience that.
Let the kid fuss. Over time, you may be able to pay some attention and learn when the fussing will become crying, and what might happen that settles the kid down.
The three immediate outcomes are crying, continued fussing, and settling down. The eventual outcomes are crying or settling down. If you respond, you don't let the kid settle down. Why not give the kid a chance to figure that out independently.