There is no restriction in the US Air National Guard Or Air Force.
There's a difference between filling up your tank on your way home, and being seen in the PX at 2000 in PTs.
Depending on where you are - you're not authorized to be off-post in uniform. You're allowed to only be in your vehicle headed to or away from base. But that's in response to direct threats.
I actually liked greens, I wish we still had them or at least I wish we went back to pinks and greens which service khakis would be awesome. The ACU is a uniform of the day on every base, unlike the Marine Corps we allow our guys to do more than just fill up at the gas station. Yet I don't wear my uniform unless I have to and never do it on civillian flights unless it says so in my movement orders.
What bothered me a lot was seeing guys off-post with their ACU top removed, more times than not they were NCOs.
Calling them out didn't always go well as I was a joe, nonetheless they made the rest of us look like ****.
When I was a Midshipman at USNA, when we were on leave we had to leave with our SDB's on. During the summer season, we had to have our summer whites on for leave and liberty, but no other uniform was permitted for wear. That being said, at airports I see a lot of soldiers in their ACUs and soldiers in civvies but with ACU backpacks or those you can immediately tell are soldiers
I have mixed feeling about this.
In one sense, they look very comfortable to wear.
On the otherhand, they don't look "squared away" as compared with the service uniform.
Usually the military would like to project a good image in public with a sharp uniform. For me the ACU dont look sharp.
Wish they would wear service caps more often than berets though. Service caps look sharper IMO
Currently the actualy "service uniform" seems to be ACUs and has been for a good while.