Or, some pros are afraid that clients won't want to pay if we initiate the call. Your clients will be happy to pay you for helping them out. They rely on your guidance, experience and wisdom. Then, it's too late. This is often misunderstood.
Some people think they're useless.
If your clients are underwithheld or haven't made estimated payments, there's still time to fix the damage. If you can change their withholding, help them save money, help them plan extra deductions before the end of the year - you'll be a hero. If you're not really clear on the rules, find someone who is and set up appointments so you can both meet with your clients. They need to know the alternatives and how to use them. But, if you don't meet with them, some financial planner or broker, referred by someone in grocery line will.