How do you respond when someone says "Thank you for your service"?

I usually say, very nice of you Thanks

Thank you !
You' re Welcome !
Appreciate that !

I smile and say. "You're welcome". Also it has happened to me that a conversation would start and the person thanking me wanted to know what I did and where I served. I will gladly have a chat with that person. Plus if that person is young I will recommended joining any service that interest him or her.

"It was no problem, I got to play around with cool helicopters, shoot machine guns and blow things up, and the best part, is the Army paid me to do it!" This leaves them with a chuckle and we part ways.

Just simple your welcome my pleasure for 21 years

Being a Vietnam Veteran, I never heard those words until recent years. It is my opinion that almost all people that say it totally mean it. I may be wrong, but I do think that most Veterans deserve it enough to have the courtesy to reply at least "You are welcome". It never bothers me rather they are civilians or veterans, there are some great conservations that follow. Then I wear my Vietnam cap or see someone wearing theirs, it has started conversations that were heart-warming. I was drafted and believe; we served for the man beside us and then our country. We were all just doing the job asked of us and the enemy soldiers in the fields the same. Be thankful for any well-meant thanks you get.

"Thank you for your support"

I say Thank you. It was one of the best things I’ve ever done. I would definitely do it again. If it’s a young person, I always tell them, “You know, the military is looking for a few good men and women.”

Thank you and you're welcome

I generally just give a lukewarm response; but, when I am caught off guard, I say, "whatever that means." Thank you.
But, yes, I personally think no one owes me, personally, anything. I just volunteered to serve (USMC 1969-71) because that was the thing to do. I didn't think I was doing anyone a favor. And, one capital thing you learm in the service is that you do what has to be done, reardless. Althought I firmly believe that my service dureing war time was a heck of an experience, I seldom feel anyone owes me thing. If anything, not a pun, thank God I came back alive albeit no whole, is that I feel I have complied with my basic civid duty.