Should you salute gate guards?

Ive been out of uniform since december 2000, and i salute uniformed soldiers all the time.
My reasoning?
1) respect
2) to let them know i support them
3) i miss being in uniform

Its that simple for me.

A salute even going back to medieval times was a sign of respect between fighting Men. Not to return a salute is a show of disrespect to the person that rendered a salute. The salute is done with the right hand in tradition to show that hand bears no weapon as most people are right handed. Upon entering a gate to a Military installation and the gate guard salutes, return that salute if You are in uniform or not. Even walking If a junior salutes an Officer in or out of uniform under proper protocol that Officer is expected to return that salute. Any officer in civilian clothes should be saluted as long as You have the knowledge that person is an Officer. All Officers and Warrant Officers of the United State Armed Forces should be saluted as well as Officers and Warrant Officers allied with or friendly to the United States. A nod or greeting without a salute is only acceptable if both Your hands are full and returning a salute is not possible. Whenever possible the right hand should be kept free to allow a proper salute or return salute.

Indoors salutes to Officers are required only when reporting for the first time during the day. If You work with an Officer in the same office area repeat visits to His desk in the same day would not require a salute on each return trip. That first salute should of course be returned and hold You salute until it is. The reporting may be given with a phrase such as Sergeant Jones, "Reporting as Ordered" as one example. Once again not returning a salute is a sign of disrespect.

I have taught Military Customs and Courtesies to both Members of the Armed Forces as well as Cadets None of this is complicated. There is no substitute for proper respect. Take pride in that salute !

I am glad to have read this post because I have never been sure about what the appropriate response in civvies should be. In uniform I salute back but most of the time I am in my civvies so I would give them a wave instead. I think I am going to start saluting in my civvies because it just seems like the respectful thing to do. They deserve the same respect back that they show when they render their salute. Thanks for the post LTC.

I think it is belligerent of an officer that doesn't return a salute. It is the same when I say Hello to a stranger...

I don't think it should be mandatory but saluting back, civvies or not, is returning the respect shown to you so I say continue for sure!

You would be absolutely correct sir!  Regardless of what uniform or clothing you're wearing, you're still an officer within the US Army.  Ettiquette requires the guard to salute you, however return of the salute by the superior is NOT required. 

You may not be “required“ to return the salute while in the vehicle, but many soldiers unfortunately view the salute as a sign of subservience, and they try to avoid doing it whenever they are not “required”. I wish everyone would be the salute as the earned privilege to show mutual respect for a fellow soldier. Therefore, I will always return the salute, whether I am in a vehicle, in uniform, in civvies, whatever.

COL: I always return a salute when it is rendered, even from a vehicle. I always make it a crisp salute as well. I am usually in civilian attire too since I am retired. It may be "old school" but that was the way I was taught. COL L

I always do. ( When I as a butter bar; I asked a friend who was prior enlisted security forces, he said they think your a dick if you don't...) So since then, its been 10 years I a salute every time.