Bandit I think you're quite right. You only need to do anything if it stops you getting on and doing the things you enjoy. I think that a diagnosis is only given if the sensory stuff is actually getting in the way of your living your life, so if it isn't, then you're not classed as ASD, iyswim.
My dh and I are both quite sensitive so we are happy to live in a noise-free, smell-free house together.
I'm taking action because my sensitivity to taste makes eating difficult, and I have a lot of food intolerance, which needs fixing. It came on post-natally, so could be anything, but this avenue seems worth a try.