Non cancellable means that they can't drop you if you're an accountant that decides to become a cop
(or something else with a bigger risk profile.)
I'm still carrying a disability policy I got nearly 40 years ago. It had an inflation adjustment but premiums increased
when that was exercised as well, so I opted to stop doing the increase to keep the premiums constant.
Self-employed/own my own company, when I got the policy it was about 80% of my income, it's way less than that
now due to my earning more -- you may want to take earnings growth into account and talk options with your
agent. (For me that meant re-applying and paying even more, but the income I'd get from the existing policy would
cover bills so I didn't do anything.)