Make sure to read the fine print. Most group policies pay only 60% of base salary if disabled. So, if you have overtime income or bonus income that you depend on, the group policies are lacking in coverage. Also, since the employer pays the premiums, your disability payments are taxed. And lastly, the term ‘disabled’ is usually not worded to your benefit in group disability policies and might only cover two years of disability and then they will expect you to find a job that you can do with your disability.
The best bet is to buy an individual disability policy from the likes of Guardian or some other insurance provider with true “own occupation” protection. Either opt out of the group coverage provided by your employer and buy a individual policy or buy enough individual coverage to supplement the income that is not protected by the group policy.