Serious is a matter of opinion.
Life changing, certainly.

My BOB used to weigh much more, now 35lbs is pushing it for any length of time.
I used to drag critters out whole, now they come out in chunks.
Long drives were normal and fun, now every two hours or less its time for a walk.
Adapt, improvise, overcome. Always cheat.

Years ago I taught people how to fight, hands on arrest control.
Now its fight ending quick kill only. The messing around being nice is too risky.

I taught a ccw class recently with a one legged customer. He uses crutches, has for 40 years. But for him, we adapted the methods and styles to fit his needs.
Minor things like spare mag placement, holster selection, become critical when you start having to do things differently.