During these times every firm needs to be more prudent when extending credit to their clients because once the services have been rendered and the tax return or audit is complete your firm does not become a priority for payment for another year. Don't fall into this trap.
A life long friend and mentor who practiced law told me very early in my career to "Get your fee when they need services or risk not getting paid". Over the years this became some very sage advice as it played out several times during my career. In almost every case where I was not getting paid I could look back and see where I was not assertive in collecting my fee.
Many practioners tell me that the collection of fees is stressful as they don't want to upset their clients and risk losing their business. Go figure! This argument reminds me of the housing crisis mess and the number of mortgages that were given to people that couldn't afford the payments. Who is ultimately responsible? The one extending the credit of course.
I recommend that every firm adopt a firm wide credit policy to make sure every client is treated consistently. In this policy require payments in advance of the services being performed and if payments are not made the firm will stop work until the money is received. In addition make sure you have a "stop work" clause in your engagement letters to support this policy. Once adopted, publish it and furnish a copy to each of your clients. Do this now. Life will be less stressful and your firm will be much more profitable.