My parents gave me one for my 21st Birthday. Lifetime fishing, small game, big game (and archery?) for New York. This was back in 1994, just a few years before I moved out West, were I've been ever since. It was one of the most memorable gifts I've ever been given, even though I don't use it. When I retire and can travel more, I'll be taking advantage of it.
With that... when I'd been in Missoula long enough, I was going to buy a resident Montana license. In going over their regulations, it mentions that you cannot have a resident license if you posses a residence license in another state. Which makes sense, because I know falsifying residency in western states for tags is a 'thing', or was. But what about these Lifetime License situations?
Being the Boy Scout that I am, I called the office in Helena to explain my situation, all while keeping myself anonymous (I'm a Scout, but I'm not stupid). When I called back days later after they tacked down some guidance, I was told technically it IS against MT state laws. However the tone was one that communicated "Yeah, technically this is a violation, but... tracking YOU down is not a priority".
I then called the DEC in Albany to explain what happened. Ended up talking to some brass in the licensing bureau who was clearly frustrated for me, sounds like I wasn't the first to call about this scenario. He basically stated that they are never going to know and they are incorrect in interpreting what Lifetime License privileges mean for New York. He ended the conversation saying "We got to get our solicitors involved in this".
Anyway, I just bought the MT resident license, and other states where I've lived since, and haven't had a problem.