As they get older, they do learn some coping skills which can help with behavior, but there are always going to be triggers. My 20 year old still has meltdowns, and his issues are mostly centered around self injury. But I cherish the good days. I find that most of his meltdowns are also related to sensory issues which cause him stress, which he just can't handle. And then when he's stressed, his sensory issues are heightened. It's a viscous cycle. I always point out when he has handled something well. Like I might say, "Hey I know that place was noisy, and I could tell you were getting agitated, but I'm proud of they way you kept it together until we got out of there." Pointing out when they've done well helps them build confidence in themselves.