I’ve heard and read that when you remove and install the head, you need to re torque the head studs after a certain amount of mileage. true or false?
I have never done so I just TQ them down to 5ft lbs from the start. I just move them by hand to see if the feel loose
5 ft lbs is a lot!! i’m surprised you haven’t snapped any headbolts 
if they’re torque to yield then i would say no, just make sure the threads are clean, there’s an extremely small amount of oil on the threads and you’ll be good. if there’s a fixed value then ya, take off the valve cover and see if they’re still at the value they should be!
Years ago, when I first went to an authorized Acura dealer to have the car serviced (it was then 6 years old), I asked that the head be re-torqued for good measure. The service tech first asked me if the head had recently been taken off and I said not that I know of. He said that for as long as the head hadn’t been “un-torqued” since it left the factory, it should be good. This sounded new to me since I remember the Mitsu dealer recommended to my Dad that he have the head on his Colt re-torqued once in a while (can’t remember the frequency, but I think my Dad had it done every other year).
Mitsubishi at the time didn’t use tq to yield bolts or if they were like Toyota the engineers fucked up on the specs like they did on the 7M.
How is 5 ft lbs a lot for studs?
And his talking about head studs
it was extreeeeeeeme sarcasm lol… i know 5ft lbs can be produce by a 3 year old with a 1/4" rachet 
lol… its one of those days my little girl kept me up