Add up what you'll earn between now and retirement. If you're forty and earning $70,000, that's over $1.5 million still to come. Most families insure the car, the house, even the phone, and leave that number completely bare.
Disability insurance is paycheck insurance. If illness or injury stops you from working, it replaces part of your income, commonly somewhere around 60%. That sounds unexciting until you notice that a long disability does everything a death does to a family's finances, except the expenses stay and often grow.
If you have coverage through work, good, now read the details. Group long-term disability usually replaces a slice of base salary only, not bonuses or commissions. If the employer pays the premium, the benefit is typically taxable when you need it, which shrinks that 60% further. And the coverage usually ends when the job does. An individual policy costs more but it's yours, it can follow you between jobs, and benefits from premiums you paid with after-tax dollars generally arrive tax free. I'm a broker, not a CPA, so confirm the tax piece for your situation.
The definition of disability matters more than the price. An own-occupation policy pays if you can't do your job. An any-occupation policy pays only if you can't do much of any job, which is a far higher bar. Two policies with the same premium can be very different products because of that one clause. Yes, Social Security disability exists, and it's a real backstop, but its definition is strict and the approval process is slow, so I'd treat it as the last layer rather than the plan.
Every policy also has an elimination period, the waiting stretch before benefits start, often 90 days. Your emergency fund's job is to bridge exactly that gap, which is one more reason sizing it deliberately matters. Longer elimination periods mean cheaper premiums, so cash in the bank literally buys down the cost of the policy.
This isn't individualized advice, it's a map of what to look at. If you want help reading your own situation, the free needs analysis covers income protection alongside everything else, because a plan that protects everything except the paycheck isn't much of a plan.